My brother bought a new car through something similar, might have been the same outfit. He said that a) he got a good but not great price (thinks he could have negotiated a tiny bit better of a deal by himself), and b) he still had to take delivery, and deal with final paperwork at a local dealer, so he still had to deal with the pricks at a dealership.
He knew going in that he wouldn't get the absolute best price, but felt it was worth it if he could get out of it without having to talk to anyone at a dealership.