This game is awesome. I think anybody owning a PS3 should have it, but I know where you're getting at. No matter how much research you do, you never get the real experience. I've made tons of mistakes when buying games, so I know what you're talking about. But you can't go wrong with a game like LBP. I would try renting it, if you're still not sure. Game rental services are very helpful when you don't have demos on PSN all the time.
I wish I rented it first. Hate the game and sold it back. We had hoped for a fun puzzle game and instead got this social networking game which is super boring. We kept playing it hoping it would get better but it NEVER did. Rent it first, do not buy into the hype.