First Phenom II X2, Athlon II X2 benchmarks

Xbitlabs has some preliminary benchmarks available.
It's surprising to see the increase in L2 cache to 1MB, up from 512KB, in the Athlon X2, while the Phenom X2 retains the 6MB of L3 cache and the Athlon II does not. The models are the Phenom X2 550 - at 3.1GHz - and the Athlon X2 250, running at 3GHz. More after the jump.

According to the article, for the Athlon II, AMD is reutilizing the L2 cache from the two disabled cores and not building new cores from scratch - these are binned quad-cores still.
What seems strange is that AMD would reutilize the L2 in the X2, while the Athlon II X3 and X4 would be reduced again to 512KB of L2 per core. We'll have to see how that unfolds as the X3 and X4 show up, but a better resilience from the cache design could allow for an efficient recycling of the otherwise unused L2 cache.

Personally, I'm going from the X2 5600+ 2MB L2 I have to triple core, at least, but the Phenom II X2 might be a good choice for someone with a tight budget. It manages to compete with Intel's E5xxx cores while delivering good overclocking capabilities of around 4GHz clock.