Tegra 2 isn't a processor is is a chipset, it uses the Cortex A9 for the CPUs and it pairs them with a low-power nVidia GPU. I don't know which is best, you'll have to wait until someone has done benchmarks which you can compare. I've seen iPad2 vs Motorala Xoom (which uses Tegra2) benchmarks, the iPad2 comes quite a way ahead of the Xoom in GPU performance.