All the problems I've had (barely audible whirring noise from a fan/hard drive, grease on the glasspad from keys touching it, slanted function keys, and a slight gap in the battery cover) are all tolerable. I didn't take mine back.
If you expect perfection, you won't get it. If you can live with a few flaws, the MacBook is a great machine. Very sleek and sexy, and super fast.