I've ever shot a friend's wedding.
I got all the photos from everyone including the bridal shop 'pro'. (Friends- D7K; A700; 'pro' - D700; D90)
I'm not BS-ing you when I tell you that the K5 had the best o/p.
At the end, my conclusion was that the photographer mattered more than the camera as all of the cameras were good enough for the day.
For weddings, I'd say while Pentax K5 can deliver the goods, I can see why most professionals will use a Canikon - FF still has the edge over APS-C for high ISO shots, and you get access to all the f/1.4 lenses (24, 35, 85) or faster. You won't always get to set up your flash in time, and well, the high ISO for FF is just so clean, at least 1 stop advantage gained I'd say. So there goes my hopes of having excuse to buy more lenses to share with my wife (she's doing wedding photography nowadays)...