B70 or R9700? (help decide)

True, but other architecture stacks are improving and people are putting in the work to optimise for teh price benefit they get.
Your use case and your time make or break the value proposition.
I agree with you nvidia is very well positioned, but there is space for other options. I am watching general ecosystem and development push.
I have supported (bought) Intel’s forray into the GPU market. But AMD is really pushing on many fronts and on that metric alone, the R9700 looks to benefit the most, I believe.