I have it. Can get pretty repetive and I had difficult working my way through the puzzels sometimes, but I find it fun. Rather generic though as your character is just some random Ghostbuster in a mansion and there's no real storyline. I'd only really recommend it if you're stuck waiting at a lot of places and you don't have anything else to keep you busy.
You just go around finding keys to get your way passed lock doors (what else are keys for), fighting ghosts all over the place (duh). You just shoot your beam at the ghost and its sucked in and “trapped” automatically. I never got to the end so I don't know what the Stay Puft battle is like.
I can't really tell you if its worth getting or not though because we all have different tastes and what I find fun may not necessarily be fun to others. Besides, I'm not that hard to impress. If I had to say though, It's passable IMO and can be overlooked. I think there's supposed to be another mobile Ghostbusters game being worked on, might wanna wait for that.