I order from this store monthly. It is expensive but you can find so many unique odds and ends. The clothing is great quality and the reviews are very helpful.

UO Online is the BEST THING EVER! They always have sales and shipping is usually free of purchases over $50. (They've changed it on the Canadian side now, but it is still worth it)
If you do not like what you have purchased, you are always welcome to return it either via mail, or even in store (as long as you have the original receipt).
Also, they let you see people's reviews and ratings on clothing items, as well as allow you to see whether or not the clothing item you seek is in-store close by to you or not.

As for service, they do a great job most of the time. Sometimes shipping takes forever during high-volume seasonal times, but it is not the worst. The clothes can be pricy at regular price, but check out the sale section. It normally has quite a few items there that you can find good deals for.