We were able to get our PS3 controllers working with our OUYA, which was fairly straightforward once we had the procedure right. Now we have enough controllers in the house to play some of the 4-player OUYA games, should we so choose.
We also got the OUYA version of Plex working. For this, we had to plug the OUYA into our home network with an Ethernet cable. The OUYA's own wireless connection, for whatever reason, was just too slow to allow streaming video. With the Ethernet cable attached, Plex seemed to work just as well as it does on our PS3.
One unhappy moment, though: while playing the first-person puzzle game The Ball, I got a prompt asking me whether I wanted to purchase the game so that I could play the additional levels. I didn't see a price listed on the screen, so I clicked the Purchase button, assuming that the system would then display the price and prompt me to confirm. Nope: the system just went ahead and charged my credit card, with only a brief message that might have told me how much I'd been charged if it had remained on-screen long enough for me to read it. Every other OUYA game has been pretty up-front about how much a purchase was going to cost, so I'm going to send a bug report in for this particular game. Fortunately it was only $10, and I'm enjoying the game, but I really would have preferred to know ahead of time what the damage was going to be.