I could be wrong here, but I think REI changed their Safari the other way- from all 26 (with disc for the past two or three years) to 26 for the smaller sizes and 700 for the larger sizes ala LHT and Atlantis.

Since most of our bikes (my wife`s and mine) are mountain bike based, I`m sticking with 26 inchers simply because it makes mix and match so easy. If I had a shed full of 700 or 27" shod bikes, I`d look for that size in my next purchase.