They do have good prices. I've been reading up on them lately and, by and large, the majority of the opinion is that they are pretty good. Of course there have been some problems, some unhappy customers, some mix-ups. They have something, supposedly in stock, that I want quite badly and shipped $100 less than the cheapest price I can find locally. Of course, I don't have an FFL, but my local favorite shop will do it for between $15-25 (depends on whether it's a clerk or the owner who handles the transfer). Still haven't decided though.
BTW, that is a very tempting price on that M&P. If I hadn't already bought mine, who knows.