Bill, I own the 70-300VR, 300F4 + TC-14E and 70-200VRII + TC-20E III and know of a friend that his 80-400 is a little bit too soft at 400mm.
You probably should go with the 300F4 + TC-14E. Good quality, almost no need to stop down, low price, but not much flexibility (and no VR!). Of course, there are better (faster) and more expensive options ;-)
The 70-200VRII + TC-20E III works very well for me at 400mm (stopped down a little), but unfortunately this combination suffers from focus shift when stopping down at shorter focal lengths, which makes autofocus a bit problematic, e.g. at 270mm.