Express is a kind of a transition store for those of us in our mid-twenties that are too old for much of what's in store at Forever 21 but too broke to shop at Macy's, J. Crew, whatever. If you get on their email list, you can get a lot of coupons for $15 off $50, $25 off $75, etc. They have sales going on all the time too. Things can be pricey at full price, especially for basics like t-shirts, but you rarely have to pay full price. Sometimes I feel like I'm paying double for the same sort of thing I would get at F21 though, especially with their tops. The clothes are decent quality.
I especially like their jeans. They fit well and are made well. It's hard to find a good pair of jeans that fits properly in rise, length, etc. but I usually can at Express. I've bought a few dresses and accessories there that I love and have received many compliments on.