The VRAM issue (not really with the VRAM but with the core), doesnt change the performance of the 970. It still performs good.
Unless you really need 4 gb you shouldn't encounter the problem.
Other factors like CUDA, MFAA, heat, physix should probabily impact more on the card choice than the VRAM issue.
But if you want and dont really need the Nvidia features you could buy a r9 290x or 290, that way you dont support these shady marketing schemes and you also give the finger to Nvidia.