I'd say its worth it easily. I was pretty hesitant to get it too, but I love it. Its even more worth it if you have both a PS3 and a Vita, both games are virtually the same. They even share all of the data (Outside of Trophy Unlocks).
The gameplay is simple, but theres also lots of combo's and more complicated things to learn. And from the looks of it, the developers are trying to keep the game balanced/alive for a long time.