Director Joseph Kosinski has two films on his resume: one was scored by Daft Punk, the other by M83. Clearly that's a dynamic that he finds very interesting, and it pays off quite well. Each of those scores is a significant departure for their respective bands' typical musical stylings, but each is nevertheless excellent. While I overall prefer Daft Punk's Tron Legacy soundtrack, M83's work here is also great, with quite a few fantastic pieces. "Waking Up," "StarWaves," "Earth 2077," and "Oblivion" are my favorites, and there are a few more excellent tracks that certainly earn the album's full price (and certainly the current $5 promotional price).
Interestingly, while Daft Punk was not involved with this score, there are at least a few songs on it that sound like they could've come straight out of Tron Legacy. This would seem to suggest that Kosinski is a fairly hands-on director when it comes to his films' scores, although the similarities could just be coincidental. At any rate, M83's work here isn't quite as consistently great as Daft Punk's work on Tron, and there are more than a few tracks that don't quite distinguish themselves, and sort of amount to "filler," but those are definitely outweighed by the standout tracks.
Long story short: if you liked the Tron Legacy score, you'll like this one as well. If you like M83, you'll almost definitely like this score (especially the final song, which may be a little more akin to their standard music than the rest of the album). I strongly recommend it.