The 6300 is a better choice. It's quite similar and generally better at the simple things(usually in x6 1100T territory) but it has a few more features that will make it a better performer in things that utilize them. Should you decide to overclock it the task will be easier because of the unlocked multiplier. Lastly, heavily overclocked power draws I've seen for the piledriver 8 cores in reviews have been lower than heavily overclocked Phenom II 6 cores, so the piledriver 6 core should be even better off.
By the way, you probably could have just stuck to the 1 thread in the AMD CPU section.