I have one that we were evaluating at work for some metrology applications so I have used it quite a bit; I have also tried it for family snapshots, with mediocre results. I think the review in Popular Photography magazine pretty much nailed it by calling it a toy. Fun to play with. Completely different than a regular camera, but mostly in negative ways. Under the News forum there have been some Lytro product announcements with a stream of comments posted. The majority of people have blasted it. somewhat unfairly in my opinion. But mostly they are correct in everything they say.
I have fun playing with the Lytro, but the vast majority of people would be disappointed in the low resolution. (one megapixel) and lack of conventional controls. On the other hand, the ability to give the user the ability to focus near and far in the same image opens up a whole new creative channel. On the other hand, a lot of people think you have to have at least eight megapixels or a picture isn't even worith looking at. But if you are up to the challenge, you can make an interesting object, tell a story, or draw the viewer into a game you dreamed up with only that one lowly megapixel. To get a good result requires an entirely different way of planning and executing a shot. There is very little in any conventional camera photography book to guide you.
If you think of photography as something you do for fun, and this sounds like fun to you, I imagine you would have some fun with this camera. Is that worth $400 to you? Maybe, but for the vast majority of people, probably not. For $300 you can get some truly amazing cameras like Sony HX20V and enjoy playing with a variety of special effects and scene modes.
If you are wondering if the Lytro can do some conventional photography in a satisfactory way, but also have the added refocus capability, I would have to say no, it is not good for that. It is really not satisfactory for conventional photography. Almost any P&S camera is better. You should only consider a Lytro if you want to try something completely different. Check out the pictures on the Lytro website and see if they look interesting to you.