From what ive read the PQ of the E6500 is identical to the E8000, while the VT50 is clearly better than the ST50.
I've had both the 60ST50 and the 60E6500 - and the PQ of the ST50 is definately better, blacks are blacker and picture pops a bit more due to the contrast.
So in my experience i would think it would be VT50 > ST50 > E8000 = E6500
Worth $1600? I'd say maybe depending on how much you value PQ since (to me) the E8000 would still lose to the ST50
Id say the VT50 is 2 classes above the E8000.
Closing the value gap, id consider an ST50.