I generally like Vin Diesel's movies and I enjoy Sci-Fi, so I was going to see this regardless of what any reviews said. In the end, it felt like it just barely qualified in being worth seeing even with those things working in its favor.
The trailer looked really cool for this movie, but you still had to wonder why it was being dumped/released during the Labor Day weekend. Now I know.
It wasn't terrible, but it wasn't all that good either. I'm not sure if the story ever grabbed me and really never made that much sense to me. I never really cared what happened to any of the characters. It just seems like an underdeveloped movie that could have been better with more content and better direction.
If you like Diesel and dig Sci-Fi movies, you might be OK with it, but even then, don't expect to be amazed by it. Keep your expectations in check (i.e. low).