If one is extremely critical regarding image quality, even the incredable performing current Nikon 2x (TC-EIII) might be somewhat disappointing on the 70-200 f2.8 VRII...although for a lot of uses its remarkably decent....but put that same converter on the 300 f2.8 VR, or the bigger fast Nikon primes, and it results in astonishing performance....not far off from the 1.4x...that good! Again performance is both light quality and subject dependant (of course). I used and tested these combinations and I too am not only "not a fan" of 2x teleconverters, but try and avoid these converters unless it becomes absolutely necessary. This high level of performance with the new 2x was also confirmed by some other top pro's using Nikon long primes. Nikon's 1.7x which was leagues ahead of the older 2x (TC-EII), fell find behind performance wise once the new 2c TC-EIII was released, espcially on those longer tele primes. It too is scheduled for an update from what I hear.
It was it's predesessor, the 2x TC-EII that was simply horrible in my opinion, boardering on almost being useless for most applications.