Dave Meltzer's Wrestling Observer is generally the best source for PPV buys, and this week's Wrestling Observer had some info on how UFC 146 did. The card was decimated by injuries and wasn't the star-studded event that was originally expected, but it seems like it still did okay in terms of buys (subscription required):

Preliminary numbers for the 5/26 show were estimated at between 560,000 and 580,000 buys, which shows that the big shows are still holding up even with ratings down. For comparisons with numbers we’ve had in the past, this is a worldwide figure and we usually have North American figures. That was very slightly ahead of most expectations going in.

Meanwhile, TV ratings are floundering a bit. The TUF Live Finale did an average of one million viewers per MMA Payout, which can be taken two different ways. The good way is that one million mark for the Finale is higher than The Ultimate Fighter Live had done for the last five episodes of the show. The bad way of looking at it is that it is the second-lowest of the eight live FX shows thus far, and a full 600,000 under what the UFC 145 prelims did on the network. With UFC on Fox ratings down as well, this could be of some concern to the organization.

SBN coverage of The Ultimate Fighter Live Finale

SBN coverage of UFC 146: Dos Santos vs. Mir