It was ok. Some parts were a little drawn out for no real reason and other parts seemed to not have quite enough backstory to really fully understand. I felt like they tried too hard to bring back the mean colonel and sigourney weaver to be honest. It could have been a wonderful story all on its own without having to resurrect those two cast members in such strange and needless ways. It was really just a tad too long as well, in my opinion. I was ready for it to be over about 45 minutes before it actually was.
Overall the effects were really great and I generally enjoyed the movie even though I wish it was a bit shorter but with a few more details in some key parts.