I have used both a Summit Viper and an API Grand Slam, both with bars, and never really had any problems.

The bar makes it so much easier for climbing than hanging like a monkey on a stand without the bar. I set the stand up with the top and bottom as close as I can get them and still sit comfortably. Then when I stand, the bar is down pretty low and does not cause anymore problems than the tree itself does.
The last two years I have gone to Ol man Multi-Vision stands.
You climb sitting in the mesh seat and then step over it to get ready to hunt. The bar, down low makes a very comfortable foot rest and is out of the way for shooting.

http://www.olmanoutdoors.com/stands/climbers/Multivision

I must've had it backwards.  I can never remember if I have the top higher or lower when I'm explaining it for some reason.  You'd think I'd remember after 7yrs of using the thing.  

I know I have the top part just high enough so my knees don't hit the bottom of the railing.     I never have had any problems from less than 10yds to much more.

Bushmaster open shot.  Buy some  Molle straps military straps off the big auction site (this site will not let me say ****) and there is NO strain on you.  Daylight and dark.

Billy

I have the Old Old man, composite bottom and regular tube type top, It is very good for shooting  forward, but if you have a side shot the bar will still interfere somewhat. I also have the Equalizer climber, very good stand and the leveling system works great.