A few minutes in, I was wondering why I was even watching, and I came here to read the reviews. I agreed with the people who wanted to give it negative stars. But for some reason, I didn't stop watching. The first 10 minutes or so are bad. Really, really bad. The acting was bad, the writing was worse, science was poor, and the political commentary on current events served no cinematic purpose. I had no complaints about the spaceship CGI.
After the first 10 minutes, it started picking up. The next ~50 minutes was decent. Nothing special, but not terrible.
The last 20 minutes or so were poor. Not bad, but below average. This is where the CGI took a bad turn, and the it looks like someone finished writing the script by recycling scenes and cliches from other movies. Even the trick ending was recycled, and if you didn't see it coming, I hope it is because you tuned out during the crappy start, and not because you missed the foreshadowing they applied with a sledgehammer. I guess you could argue that there was a second trick, but to me it looked like that got tacked on to make the ending artificially ambiguous. I think the movie would have been better served if they had committed to one "true" version and stuck with it.
Overall, I give it 4 out of ten. On my scale, movies between roughly 3 and 7 are watchable once. I've seen, and enjoyed, worse movies, but there are plenty of better options out there.