I currently use, and so do two of my buddies, the Alpha Sit and Climb. It is a great, light treestand. Very quiet, ultra-compact and a nice set-up. One great feature is the ability to tighten/lock the climber half to the base, using the supplied strap system. The built in bow holder is a great feature, too.
Like with any treestand, you have to get it dialed in and rigged for you. The one complaint we all had was the thin seat - the supporting straps would dig into you thighs and a_ _! So, we replaced them with a thicker seat and it elimanted the only problem I had with the stand.
I also have a Summit Bullet Backpacker - very nice stand and safe. Not near as quiet though, and it does have the upper climbing wrap around bar which makes bowhunting tougher. It is comfortable and you can't go wrong with either company.