Good question.
The only thing that I don't like about the Burris 2x-7x is that the eye relief also varies. As such, although I can see through it with no problem from 2x to 4x, anything above 4x causes the scope to "black out" unless I bring the scope, and pistol, closer to my eye - but the problem then becomes that I don't feel comfortable shooting it at such a close position.
The great thing about fixed scopes is that you can set the scope in such a position that you will never have to worry about changing your shooting length. As such, you become more comfortable when you shoot.
Now, the BEST of BOTH WORLDS is the Elite 3200 2x-6x because it has 20" of CONSTANT eye relief. As such, it doesn't matter if you are on 2x, 3x, 4x, 5x, or 6x because your shooting length will always be the same because the eye relief is constant.
Now, I don't know if you want to spend more money and get the Elite 3200, but I think that it would be money well spent. In fact, next handgun scope I get will be the Elite 3200 2x-6x.
In the meantime, between the Burris 2x-7x and ANY fixed scope, I would get the fixed scope for the reasons mentioned (again, unless I get the Elite 3200 with constant eye relief).
Zachary