It's not really a sequel, they pretty much just split the Shinkenger adaptation into 2 seasons (but still considered 1 season).
Anyway while Samurai was... just... ok, super samurai has been pretty good IMO, the acting is better, and the last episode really made me laugh with the Bulk and Spike segments.
Is it worth watching? IDK, it still has it's corny moments here and there but, well, that's always been power rangers. So if you go into it thinking there's gonna be corny jokes and dialogues, you'll probably enjoy it.