I'm 5'4" and about 110-115 lbs...but I don't like the 30, esp. when I tried it on. I have bigger bags, but I think I prefer big bags that are more vertical than horizontal. The 25 is tiny, but I think it'd suit me better (since I don't hold a lot of things in my bags, anyway).
I'm 5'5" (1/2) lol and the majority of my Speedies are 30. I only have 2 (25s) Cerise, and Epi.
When I do get my Azur I'm getting it in 30. I like having the extra room and being able to throw magazines inside. The 25 is really cute, but just seems to small for what I need. I tend to use my 30s more cuz I like the extra room.
I do loving my Epi Red 25 cuz I LOVE THE RED!!!!!!!!!!!!!!!!!! (but the epi speedies run bigger though...) My cerise is so small to me. I gotta push myself to use it more often. It is adorable!! Sometimes the size hinders me from using it though...:s When I go on shorter trips out I try and use it but I can't seem to get away from my speedy 30s. lol...
Today I tried on a speedy epi in red in 25 and found it too small, I compared it to a monogram one in 25 in the shop and it is indeed a bit bigger-but not big enough for me (162cm). And I found the opening really small in comparison to the 30.
i have the 40 and in fact just broke it out again today. i am 5'3" w/medium build and it looks just fine on me. it is stuffed with kid stuff, however, and thus holds it's shape fairly well (not much sagging going on).