I have some from Stampers Best and some are Sunday International Stamp N Stor, and I just ordered some EZ Mount brand from Crafter's Companion so I could compare. I found that the Stampers Best laminated panels are a bit smaller than 8.5 X 11, and this made it easier to slide them in when full of stamps, so I trimmed the others I had from Sunday International and rounded off the corners so they now fit better.
What do people use for the index sheets? Cardstock or just plain printer paper? Cardstock is nicer, but I'm not sure I want to use up so much white CS. I just got four small SU sets on a single panel, and now I have to do the index, and am trying to decide whether to keep using cardstock or not. So far, I have been.