Right now only shipping are the Ouya pre-order and developer consoles while the game consoles en mass aren't expected until the summer for the general public, but already the performance really isn't competitive.
The first-generation Ouya is based upon a NVIDIA Tegra 3 SoC with a 1.7GHz quad-core ARM Cortex-A9 processor and NVIDIA GeForce ULP graphics. The Tegra 4 is already much faster and any Cortex-A15 SoC can do laps around the older A9s. The graphics performance out of the Tegra 4 and other newer SoCs are also a lot better than what's found in the Tegra 3.
Since July of last year I have been rather disappointed with Ouya in part due to the lackluster hardware. Ouya is nice if you are on an extreme budget and can only afford $100 on a game console, but beyond that, Ouya is not too interesting. A much better Linux game console is Valve's forthcoming console for the living room.
Today we now have benchmarks confirming the poor performance out of Ouya. On Futuremark's mobile device listing they have a list of the fastest mobile devices. Futuremark is the company behind 3DMark, PCMark, and other popular benchmarks most commonly on Windows.
The Ouya game console is presently ranked in 73rd position with many smart-phones performing a lot better than this Tegra 3 Android game console. All the fastest devices on their best mobile devices lists are Qualcomm Krait devices with Adreno 320 graphics.
Here's the individual data from Futuremark on the Ouya. The default scores for the graphics tests on the Ouya are 14~17 FPS while with extreme settings the scores are less than 10 FPS. The overall graphics and physics scores are rather low even compared to other ARM/Android devices.