I've been playing the Beta for several weeks, I think the longest I've waited for a game has been about 20 seconds, and apart from the initial few placement matches (to enable it to rank you at the beginning), they've all been reasonably close, entertaining games.
I can only assume that at retail with even higher numbers of players it will be even quicker to find a game.
I can only assume that at retail with even higher numbers of players it will be even quicker to find a game.