I just visited the LV boutique the other week to try on both Bloomsburys, PM and GM. You shoud consider also how much stuff you want to carry around. I chose the GM because I always have a lot to carry... The bag is my Christmas present from DH Can´t wait to be able to use it!!
I also think the GM simply looked better on me, as I´m 176 cm tall and not very slender. I would maybe choose the PM if I only needed a couple of things to carry. But the GM is an everyday sized bag and more user friendly IMO.
I tried PM and GM in a boutique and I got PM. After discussing with an SA which one looks better on me, we agreed that I should get PM. I am 5'6 and 138.
I love it, it holds all my stuff and I love the style.
I think it is all about your personal preferences. Try them both and see which one looks better on you...
I have the PM and use it mainly when I go shopping and running errands. It holds everything I need for the day, small makeup bag, cell phone, cles for cc's, key holder, aveda toner mist spray bottle and sunnies. It could actually hold more but that's all I choose to carry in it. By the way, I'm 5'6 and 120 lbs, HTH!