I also haven't tried Nectar, so can't help with comparison.
However frankly I wasn't so impressed by PowAir personally, when I tested it some time ago. There was some initial sensation, but after few comparisons, even after some tweaking, it never beat my usual chains from separate plugins or normal procedures. But its always material dependent of course and I didn't feed it with something, where it really shines

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With regards to gain riding and processing of longform material like your mentioned interviews, I was very impressed by ease of use and results from TB Dynaride. It has dedicated profiles for detection algorithm like speech, vocals, bass etc. and there is also switchable look-ahead to overcome possible pops. It produces pretty good results out of box with some sensible setup for target level, range and noise floor. Like with similar tools, you can use it just as straightforward effect processor or write automation to your DAW for manual correction if you need that.
In combination with some other sensibly set quicker compressor, limiter or de-esser according to your material and needs.. you can achieve quite good results IMO/IME.
If you happen use Reaper as a DAW, there are also other options for those tasks at their script collection. There are some pretty good ones, which can do offline analysis of selected clips according to riding parameters and write clip based volume automation faster than real-time. Then you can again tweak it manually and combine it with other effects as necessary.
Michal