Could you name some of them?
No I can't, or more accurately I wont, I'm just going to generalize any/most Android Mini-pc with a 31xx (42xx are on their way but irrelevant here) Rockchip series, or 44xx Samsung Exynos chip series. You're not going to get prettier-looking games Android games (Asphalt, Dead Trigger, Little Inferno) if thats what you're interested in, but you may get a few extra frames in your benchmarking scores (Really who cares), but more importantly, smoother performance with a few of those higher-demand emulated games. They're ugly as fuck, but slightly, very slightly more powerful, come with more connecting features and options like two USB slots (With an OTG). The point is most of them cost less than the Ouya. Yes they don't come with things like an extra controller or something, but some of us may already have spare devices that can connect to android like a PS3 controller or Logitech Keyboard.
But I'm not saying I want those crummy Androids for TV systems, just saying that one is no more special over the others because they all run the same OS on similar hardware. At that point you might as well just get a slimport cable and do it better on your phone. And I'd like to stay strict to the android vs android content because we're talking about hardware prices at or under $100/ Just why the hell would anyone bring consoles or PCs to the mix. The only acceptable comparison to go by here is that Vita TV, which actually interests me, because unlike Ouya, it has some exclusive games.
If you care about a console for your TV for $100, get Vita TV.
If you want an emulator for your TV for under $100, get a rikomagic or a diotech or something.
If you already have a smartphone, google your phone's model and see what you need for Video Out.
And because PS4 was thrown in the thread for some unknown reason, and you have the $450 to buy a PS4, then get a PS3.
What advantages does the Ouya have alone, that I can't already substitute with other stuff?