I've tried both, and the 700 suits me more. I'm sure it's not much more than personal preference, but I do like the easier rolling of the 700 (albeit with narrow tires. Fatter ones may not be so appealing). My cronies use a lot of 26, but I do seem to pedal easier and stay out front a lot. Personally, I haven't had any more flats on the 700's than I ever had on the 26's.