The more I play with it, the less I see the real point. From a collaborative standpoint involving documents, sure, looks good (as long as you don't mind the vague privacy terms and aren't discussing company secrets).
When it comes to photos, G+ auto uploads them from your phone and Picasa sends them to G+ as well. You would think that these end up in Drive, but no they don't. Why, Google, do I need a barrier between G+/Drive?
In terms of music, we have Google Music... huzzah! Except, again we have a barrier between the two. Sure I can upload any music I like to Drive (with the added advantage of it not being downsampled) but then it isn't accessible to Google Music. Personally that's annoying as hell to me.
So far, everything I can put into Drive is isolated from all my other Google services without several additional steps to get it there, which frankly disappoints the living hell outta me. Add to the list of negatives a very real lack of privacy assurances and I've got a very sour taste in my mouth at this point.