I read a lot of informative, interesting non-fiction, but sometimes I need to relax a bit, and depending on the mood I'm in, Science Fiction or Westerns are my preferred genres. Some of my favorite SciFi authors include Neal Stephenson, Jerry Pournelle and Larry Niven; they write interesting stuff as well as good stories. Sometimes, though, it's fun to read a good old "space opera" with "good guys" vs evil aliens. These books fall firmly into that category. Tough, strong men and women go head to head against malevolent aliens with sometimes superior technology...and come out ahead.
The first set of books is about a contested world where a foot soldier is dropped into a fight she was never expecting, and forms (in the first book) a guerilla squad to fight the aliens.
The second set is about the voyages of the Odyssey One, which makes humanity's first contact, on its maiden voyage, with both friendly and very, very unfriendly aliens.
I'm not sure either book contains any particularly novel ideas, but if you like science fiction with a military bent, they're fun reading. They both include battles both in space and on the ground with futuristic weapons, although the former has more ground combat, and the latter more fighting in space.
In short, it's some good entertaining escapist reading.