Just like a sticks and bricks home, it can be hard to know exactly what you want until you've had your first one awhile. Find the one that seems to fit most of what you think you want, and enjoy it. We really liked our 33' class A, then our needs changed and we thought we wanted something smaller, but with a walk around queen bed. Now we've had our Vegas 25.2 for about 5 weeks and 3000 miles, and know we made the right choice for us, for now. Of course, different strokes for different folks. Lots of good opinions on this and other forums.
If all else fails, read the directions!!