[Shin Henshin]

It's toku aimed at girls essentially, seeing as it's also done by Toei. But the formula it follows makes it enjoyable for most toku and anime fans.

Monster/issue of the week stuff, sixth ranger additions in some cases, power-up forms near the end of the series, it follows most if not all of that from season to season. The only difference is that since it's aimed at younger girls, it's a lot fluffier and brighter.

That said though, there are things that are entertaining for older viewers. Character conflicts, pretty good development and in some cases really dark or surprisingly complex plotlines or backstories. HeartCatch Precure is considered the best installment because it included all of those points. If the happier tone of things don't bother you, it's a great addition to watching Super Sentai and Kamen Rider IMO.

EDIT: It's more like Sentai based on the fact that it's mostly team-based. Starting with one or two members at first and increasing to at least five as time goes on.