I use CNX2, PhotoMechanic and iMatch (for cataloging). I have an old version of PS for anything CNX2 can't handle (mainly multi-image layering).
I haven't invested in NIK plug-ins so cannot comment on the various solutions to that problem.
CNX2 and the other apps let me treat a NEF file like I had a NEF+JPG, with the benefit tha tthe JPG is always current and up to date, and only one file to manage.
I've never had an interest in doing post processing in camera. Nothing "wrong" with it; just not my preference so doesn't affect my decision.
The biggest competitor now, in terms of speedy processing, seems to be Lightroom. I considered it but my 8 years of archives would not fit into that world so I keep doing what I'm doing. Keep thinking about it though. If LR handled versioning across folders that would make me think harder (big issue with me).
Tough choices- they all have their ups and downs and there doesn't seem to be a silver bullet here.