The device itself, the box, wasn't bad for what it was. It was small, sturdy, easy to develop for, could have been faster but wasn't super slow. I never found out why they didn't overclock it like they originally said they would, it had the active cooling fan so should have been able to run faster than the Tegra 3 tablets that used the same chip. Ouya should have been like the Oculus Quest, taking a mobile chip and pushing it to the edge.
Of course, there was more than just the box. The controllers sucked - aside from the design where buttons could get stuck under the faceplate, the launch controllers had a hardware bug making the analogue sticks crap, which gamers of course blamed games for having bad controls. Ouya fixed the problem a couple months later but made people buy more controllers if they wanted the fix. Even though the Ouya was delayed, the OS wasn't really ready until like a year after launch. The system's delay made it so there were like 1500 games at launch, and the OS had no easy way to sort through them.
The real problem with the device was the management of the company, their lack of communication, their strange idea that other game consoles didn't exist ("Finally, gaming on your TV, like when you were younger!")
But does it make a good emulator box though? Probably not.
These days there are better options, but it was a pretty good emulation box at the time. Also good for video streaming once they figured out how to enable the hardware features needed for it.