I bought my dress here as I was lucky enough to find the style I wanted in my size. However, it was pure luck that I stumbled across my dress, which was the only dress in the style I wanted in the entire store. As someone mentioned below, the selection tends to be quite dated, and prices are slightly higher than what you may find with used dresses online. However, there is a distinct advantage of trying the dress on in person.
The staff there are very friendly for sure. I think going with the mindset of "wouldn't it be really nice if I found something here" is very helpful. Whether your experience there is positive or not depends on the selection when you visit, I think.
A word of advice: the accessories, while more reasonably priced than a salon, are still a bit pricier than what you may be able to find online. Things like veil doesn't really need to be tried on, so it might be good to check online as well as the Bride's Project's selection.