Well I don't have either one. But I thought Niche Inspector looked good enough to blog about, so I did back in April.
Niche Inspector - Easy Niche Marketing Research
No affiliate link and not trying to sell it, just looked like it may have merit and I did see some pretty good reviews.
Niche Detector I haven't looked into as much. Just scanned a couple of the videos.
One thing I WONDER - I don't know, just WONDER is couldn't a general keyword tool like Keyword Elite do all that and lots more? I can see lots of ways to use it for niche research but then you can also use it for in-depth KW research and management. It costs a little more, but I think it DOES alot more. Maybe I'm wrong???