I had the same dilemma and really debated. I don't like carrying tons of stuff around w me so I was leaning towards the 225 for how elegant it is. But I couldn't get over how small it was and for day to day use, I felt like I was playing Tetris w my stuff .so I got the 226 .
I must say, it doesn't seem that big anymore! It's a great size and I can't do a lot w it. It's only when you compare it to the 225 does it look ''oo big' but in the scheme of bags, it's actually on the smaller size .
I was initially going for the 225 but it looks so small when I saw SA getting it out from the closet lol. I'm surprised I find the look of the 225 smaller than the m/l classic flap I have, though the measurement is only 2cm difference!