Summary: A very original concept for a relaxing game. A good replay value even if you've finished all levels. If you get it at a discounted price, that's a good deal. The kind of game you play between two games, to make another part of your brain work.
Summary: Very relaxing and beautiful, but I found that each level started out really hard, and I'd have to reconstruct the level a few times to get myself off the ground. But once you have, the ball is rolling, and it's then fairly difficult to lose unless your attention lapses.
Summary: You might rate Osmos low if you haven't tried enough of it's features; or, as a Casual Gamer, possibly overated. I'm not a full-time Casual Gamer, but enjoy them occassionaly. Osmos is an Indie game. That itself should warn all buyers it's probably going to be a unique game experience.