Upload & Sell: On
maybe I can hold my breath and Nikon will come out with a 400 f/5.6 in the next month or two
at the end of the week I plan on purchasing the 1.4 or 1.7tc, just haven't decided which yet
Given how good the IQ is from the 300mm f/4 + 1.4x teleconverter, I'd say there's not much point to the 400mm f/5.6. I do wish they'd update the 300mm with VR.
If birding is only an occasional hobby for you, I'd probably start with the 1.7x teleconverter and go from there. It's a really decent combo, extremely portable, with good image quality. I tried the 2.0x II version (not the new version) and the IQ degraded too much for me, but the 1.7x is good. That's been my birding lens up until my very recent acquisition of a 200-400 f/4 - and I will probably go back to my 300 + teleconverter after I get back from my safari.
Since you already own the 300mm, your investment is minimal, as is the storage/carrying space required.