I think it was mediocre, and that Matthew McConaughey and Anne Hathaway are the bad guys in the movie for trying and stopping Matt Damon.
Yeah I think I'd give it a 7, the actors performances were a bit forgettable (McConaughey and Chastain did well, seen them both give more inspired performances however)
As far as Damon is concerned, I found his performance a little unbelievable. I would have liked to see his character act a bit darker (bit more crazy) for how long he'd been there. I thought he was a little too level headed and apologetic for having just attempted to murder 3 people.
Cool concept, time/black holes etc. are always interesting to me, and of course the movie was beautifully shot.
Probably won't watch it again but I enjoyed it.