I was the kid who was an outcast because I watched PR still when I was 10 or so. I stopped watching (couldn't stand SPD and onwards), started watching sentai last year and depending on the series, I can't stand PR, or Sentai.
I think RPM's good, but it butchered everything I liked about Go-Onger. It could take itself seriously when it needed to, and while RPM's funny moments were funny, it's serious moments were bland. And the soundtrack sucked, in my honest opinion. Go-Onger however, had an amazing soundtrack, and soundtracks really help make the show.
I hated Gekiranger for poor characters and a blah plot that wasn't serious or joking, but preferred Jungle Fury, being the only Kalish season I can take. It took the plot of Gekiranger, but actually chose a direction at times and not be stagnant on "blah", and handled the characters better... Except whoever White was. He still sucked, but more.