Heh. The price jump to get from 6 cores to 8 or 12 is so significant that we really do need to see bench tests of real world tasks to make an informed purchasing decision. Here's a good rundown of what the tradeoffs are based solely on the CPU specs. How well-parallelized an app is will directly impact whether those 8 and 12 core Mac Pros are worth the $1500 and $3000 respective price premiums despite their lower clock speeds.
Does BareFeets have the cash to buy three or four different Mac Pros at varying spec levels to test?
I'm definitely getting the 6-core. The price difference to get a 25% processor increase (only in the best scenarios) is simply too great. Anything less than 512 GB for the drive would be problematic for me. The question is which is better - upgrading from 32 to 64 gb or going D500 to D700.