RE: Several Summit Stand Models?
I bought a Summit Viper X4 for both bow and gun hunting. The bar does get in the way when bow hunting. You essentially have to stand up to shoot although that's the case with many stands unless the animal is directly in front of you. The bar does make climbing much easier - and I believe safer. It also makes a nice place to set your bow I expect it will be preferable during gun season.
To sum it up: I like it. Its light, solid and very safe. If your going to bow hunt exclusively, the Cobra might better suit your needs. The only problem I see with it is that once you raise the bar it's out of your way - unless the shot is behind you.