I went to the store to get the GM, and I like bigger bags. I have and LOVE my mezzo, but the gm was bigger than the mezzo. It was to big for me for everyday. I didn't like the handle straps as much on the gm as I did on the pm. I can't remember why exactly though. I ended up getting the pm. If you can, go to the store and try it on, the gm may be perfect for your needs though.