USA Baby opened right before I had my baby last year. I wish it had been open sooner because I ordered a lot of stuff from the mainland that USA Baby carries.
First off, they have a HUGE selection of furniture, like cribs and changing tables. There is not another store on the island with that huge of a selection in store to view.
They carry brands like Peg Perego, Britax, MacClaren, all the higher end brands. You can find most anything for breastfeeding here as well. The only thing I don't like about the store is that they don't carry Fisher Price items, it is too low-end.
I also like USA Baby for the little cute things that you can find in there. This is the perfect place to find a cute shower gift or bedding that you won't find anywhere else.
They run sales, it seems, quarterly. They have a once a trimester sale. When a sale is going on I have seen everything in the store on sale! That is awesome, especially when you are first buying things for a new baby.