I think if you are tall, the GM is best for sure. I tried it on and kept going back and forth. If you carry a lot, than the gm for sure. The pm seemed like t would only carry the bare minimums.
I love the GM, girlfriend of mine has it and I was not sure if I should get that or the palermo, I tried on her GM and it was the perfect size, I am a small lady too. I went with the palermo but the bloomsbury GM is at the top of my list!