Zipper is my favorite. I have a 13" Extreme riser. Fantastic grip, terrific riser. This has been my experience. First one I bought was the TT black Onyx. Did not like the grip. Bought a TT Titan and is a fantastic riser. Just a terrific riser if you want to shoot off an elevated rest. I wanted to shoot off the shelf with a plunger so I sold it. The new ones I think now have a shelf set up for shooting without an elevated rest. I then bought a 13" and 15" Morrison Gen II. I like the lighter weight better than the titian. It also allows you to adjust tiller/weight while the limbs are on the bow. Allows you to shoot off the shelf with a plunger and also another higher hole to use with an elevated rest. Like the way Bob made the shelf on these risers. Terrific riser. Great value. My 2 cents.

Morrison is haveing a 40% off sale right now. He has a few risers left.You may want to check it out.

I've owned 4 metal risered ILF/DAS setups and they all were nice with some differences. 17 & 21 Dalaa, I like my ILF 21" Dalaa for target work with lighter limbs. I like the extra low grip of the 4 they offer. The 17 Dalaa was fine but I like the 21" better. The 15" SKY TDX has the best feeling grip I've owned and it is the lightest and best balanced set up, and with Dryad epic LB limbs is the bow I use hunting.  The other riser was a 19" TAC firefly, good riser built like a tank second best grip, easiet to quiet, high preload, but it's not made anymore.
If I had to pick best all around of the 4 it would be the 21" Dalaa, it is built very well and it does all things well.#2- 15" Sky TDX. #3- 19" TAC firefly. #4 17" Dalaa. #1-3 all close.
Do the more expensive limbs matter, in my limited experience I've found they do, smoother, more speed, more forgiving, just to list a few. It is again an individual choice if those things in a limb warrant a doubling of the price.

Metal is just too cold for me when hunting.  I love Bob's bows and had a 13" mini ILF but I was having a hard time keeping my hand in the same position every time.  At Denton, I got to try Bill's Zipper 13" Extreme STX and I was sold.  It's all in what works for you as everyone has an opinion...tippit