For this season, I have a new pair of wool pants, an Asbell zip-up, and a Cabela's wooltimate windshear vest to wear overtop, to both keep in warmth and keep out wind, and to keep my bowstring from catching on my left chest/shoulder.  I'm pretty happy with the setup, and looking forward to hunting with it.

But... I've never worn wool outdoor clothing before.  

Any tips, or warnings?  Disadvantages?  I know it shrinks.  Everyone says it's great for keeping you warm when it's wet.  But does it shrink if I get caught in the rain with it?  And I hear it picks up cockleburrs.  Anything else?

It's heavy.
Other than that, it's the cat's meow.

Cons:
Heavy
May affect mobility (bulky)
Thorns stick to it very well.

Pros:
Warm
Silent
Long lasting

IMO anyways.

Wool is the best material for outdoorsman, be it hunters, hikers, surveyors, whatever.  

When backpacking, the weight is criticized by some but I actually like the weight better.  When it's cold outside and you have something warm and "heavy" on it feels more cozy than something that's just warm.  

Also, some people complain of it being itchy.  This quality of wool depends largely on the quality of the fibers used to make the fabric; some wool itches like crazy and other wool is soft like fleece or cotton.  Since it's typically used in cold environments, even the itchy stuff can be combatted by using a cotton t-shirt or long johns under the wool garment as a base layer.  

The only real downside I've found is that it requires more care when laundering than a cotton or polyester/fleece product.  I don't like doing laundry so naturally I don't like taking extra care for my wool clothing but the benefits of the wool are worth it for a few garments.

Wash it either by hand or on GENTLE W/COLD water and Woolite.  AIR DRY it and make sure to come and stretch it out with your arms a few times while it dries so it'll remain the same size.  If you don't forget to stretch it back to it's original size, then it'll shrink as it dries.

I wear wool, from base layer to the outer layer.  Burrs suck, it gets heavy when it rains, it wears thin if you bust brush, and it is usually not wind proof.

You wanted the negatives...so many positives that far outweigh the negatives!  It takes a little getting used to and to layer correctly.  I do use a down vest underneath if necessary, and a gore tex outer shell if necessary too. Rarely.  Get a burr removal tool, the little block 3R sells.  Any nylon layer can cut wind, like your vest has, i think. I don't know the wool you speak of, but I have been in hours of constant downpours in KOM wool and never got wet, several times.  A friend couldn't believe it and bought it for the next year too. It resists bacterial growth and scent, and actually is not a problem when wet, just heavier.

It's so quiet, quite durable, water resistant, spark and fire resistant, and resists bacterial scent that it is really a fiber that has never been beat for performance.  You never feel clammy.

Why do you think fleece and any other synthetics always compare to wool, the gold standard?

I know it is not cheap and quality varies by maker, but the natural fibers of wool and down are hard to beat, and this comes from a whimp when it comes to being cold easy. I get cold easy and it took a lot of work to come up with what works for me.

The price is the only con of it.  God Bless

Wow, lots of quick responses.   Thanks a bunch.

I got some real thick camo wool pants from the bargain cave at a Cabelas that I happened into.  They appear to be pretty high quality, I got them over 50% off because someone (who was conveniently the same size as me) had them altered to fit, and then didn't buy.  Hopefully they are not junk.  If me and wool get along, I'll soon learn what is good and what isn't.  I like warm clothes to be heavy, so I think I'll be OK with that part of it.

But what about getting it wet in a multiple-day hunt, let's say?  Do I have to consider the possibility of shrinkage?

Not my favorite when mother nature throws some hot weather your way.

I can't wear wool. It makes me itch all over "like a leaf on a fuzzy tree".

Never been a fan of wool. It's heavy, not wind or waterproof. And, it irritates my skin.

For me the only con is the fact that it picks up burr's and such easy.  Other than that the washing isn't that big of problem, I wash it by hand in wash tub with backing soda and uv killer soap, rinse, then lay flat to dry.  Wool doesn't need to be washed as much as it doesn't hold odor as much as the other products, at least the way it seems to me.  Pick up the 3R burr remover and your set.

wool is good..... GOOD wool is awesome. I love mine and never worry about it being heavy, itchy, etc. My only complaint is that most of the time it's TOO HOT down here to wear it.... I take it with me to MO every year though- and it shines.

I can not think of any.

I hate wool.    But its almost never cold here.

The only downside I can see is that it takes longer to dry than synthetics. I wash wool garment much the same way as GDPolk says and have never had a problem with shrinkage.

Also as GDP says, the itchiness depends on the quality of the wool. I've got some wool T-shirts that I happily use as underwear - doesn't itch at all.

The Asbell pullover and Wooltimate combo you got is a good one, it's relatively light weight and will keep you toasty. It shouldn't shrink if it gets wet from rain, unless you use high heat to dry it. I always just hang it or drape it near the fire at camp and it's still the same fit. That goes for any brand wool I use, which I have a few of.

Heavy wool pants can get a little warm on a hike of any distance, for cold sits and moderate activity they are great. I just use merino under my pants and light shirts to help with the itch...

The pros and cons above are my experience. I love it for cold temps. Nice and quiet too.
I haven't noted any shrinkage after getting mine wet.
Read what Thresa Asbell has to say about wool care on their website. She hand washes ALL wool products, air dry with stretching back to original size as it dries and NEVER twist/squeeze the water out of it.
Mine hangs to dry in the basement after a wetting in the outdoors. I've always dry cleaned mine when dirty, but her tips sound good.

I used to have full sets of KOM and Sleeping Indian. Probably spent a couple thousand dollars on wool at the time. It had and has plenty of positives of course. You asked for negatives, so here's what I didn't like so much:

Physically heavy and bulky to pack.
Burrs will run to wool and jump to get on it.
My wool retained odors that I could easily detect.
Dry wool is a sponge, waiting to absorb any water.
Wet wool is very heavy and slow to dry.
My premium wool wasn't as wind-resistant as I hoped. I had to top it with wind-proof layers.
Dry cleaning is inconvenient, but best for wool.

Having been down many roads, I found other non-woolen garments which suit me much better in cold, wet weather. I sold every last piece of my premium wool and haven't missed any of it. The only wool I wear these days is Wooltimate (wool/fleece blend) by Cabela's, and I only wear it when hunting my local whitetails. I haven't worn any 100% wool for many years, despite traveling to some far northern reaches of the continent.

I wear wool extensively. I have never had it shrink from getting wet in the field. Let it dry, maybe block it ( gently pull it) a few times. I have had it on in the field and gotten soaked. White out rain storm soaked. The worst time I was out for 2 days. I wore the clothing until it dried. No shrinkage, no cold. My wool clothing requires A LOT less maintenance than my bow, wood arrows, feather fletching, and shooting glove.

Burrs...for whatever reason, they don't bother me. I get them.....heck, I hunt mostly in Michigan. But I just pick them off. Those lava rock burr removal thingys work well. But if my hunting clothes have a couple burrs, I just don't care.

The pros of wool waaaaaay outweigh the cons. It is warm, yet comfortable in a wide range of temperatures. It truly is warm when wet or damp. I know this, I'm not just recycling what I have read.

I feel extremely camoflauged when wearing a subtle wool pattern It absorbs the light, it is SILENT (a significant component to the camo concept). It isn't bulky. If it is, it isn't a garment designed for bowhunting. I have some Filson Mackinaw coats. They are of awesome quality, and I like the style. But they are designed for timber cruising, not shooting a bow.

I also wear a wool sweater a lot these days. Remember how hot they are when wearing one to the office? I do. My wife cringes when she sees me wearing an expensive merino wool sweater as a hunting garment...I almost delight when I have a good sweater get a hole or stain.....because now it goes into the hunting pile      

I never feel like my wool is too heavy. If I am wearing heavy Filson gear, it is cold enough that weight is my last concern. Most of my hunting wool is Asbell pullovers, zip ups, and vests. I also have a lot of the good old Woolrich shirts. A REAL cold day on stand might find me wearing merino wool long johns, a wool sweater, a Woolrich shirt , and an Asbell pullover or zip up. I will throw a vest in the bag as backup. I never get cold. If I am moving I would drop the sweater or shirt.

I don't find that wool retains odors anymore than other fabrics. I don't smoke, and I take reasonable care to stay out of stinky, smelly places regardless of what I am wearing. I care for my hunting clothes by wearing them, airing them out, and washing them if they are dirty. Wool or cotton.....the outdoor breeze deodorizes them better than anything else.

When I was stationed in Germany, we were issued crummy GI cold weather gear. Mostly quilted cotton stuff. The first thing I did was send home for my wool shirts. Somewhere I have a picture of myself in the field. I stand out from the crowd, because I am the only guy with a buffalo plaid wool shirt peeking out from under my bone chilling cotton field jacket.

It's great when it's cold but I wouldn't wear it in the Summer if I were you.   It can get pretty hot.