IMO Acrylic everytime, its lighter and tougher. Practically unbreakable. The only negatives are that its more expensive then glass and scratches easily.
I'd go with glass everytime,i have a couple of small acrylic tanks and they're have got lots of scratches on them from the algae pads.i don't use them now.
I don't mind small acrylic tanks, they're nice for a few things, like a betta tank or some guppy, but anything over five gallons I'd want to be glass, hands down.
I've been neurotically careful with my acrylic tank as to not scratch it. Well, guess what? It still has managed to become scratched up all over the front and sides. I have NO idea how! My others are all glass and have maintained their appearance.
have you seen a 100 gal acrylic tank? They are far from flimsy. It is a fact that acrylic is stronger it does not crack easy. But it does scratch easy. Humm I'm going to go look at a glass tank tomarrow.