Get the Nexus 7.
I've got a tablet with similar hardware to the Onda V972 (Nextway F9X, 2048*1536 9.7" display, Allwinner A31, PowerVR SGX544MP2, 2GB RAM) and while it works more or less okay, the A31 chipset is still too new and the bugs haven't all been ironed out yet. No sources available so that means no CM10, either.
The CPU is a Cortex A7 1GHz quad-core and isn't quite as fast as Tegra 3. It is, however, faster in terms of GPU, I believe. App compatibility already tends to be a crapshoot with off-brand devices and the unusual (for Android) 4:3 2048*1536 resolution just tends to exacerbate the problem. Meanwhile, the Nexus 7, given its popularity and direct software support from Google, quite possibly has the best app compatibility among Android tablets.