Keitai Sousakan 7 > Kiva > Rescue Force > Go-Onger
Kiva and Keitai are the only ones that I actually feel the need to watch an episode the second I get them, well, lately for Kiva anyway, I didn't see anything too great outside of the 1986 story until recently. I sometimes let the Rescue Force episodes just pile up, but it's a pretty fun show to watch, I just don't have as much motivation, and I've dropped Go-Onger, so that says how I feel about it. I may go back and watch it since I dropped Boukenger and ended up finishing it...right now I just don't see any redeeming qualities in Go-Onger.
Fairly confident my rankings are going to be like this by the end of the year as well.