For some pretty good military sci-fi (not syfy, hate that they did that...) give a look at "Terms of Enlistment" by Marko Kloos. It reminds me a lot of Heinlein, not so much because of the social commentary, but that it's a grunt point of view.
Also another one of my favorite authors, Marc Edelheit; Start with Stiger's Tigers (it's book 1) or Stiger - Tales of the Seventh (a prequel, followed by Fort Covenant). It popped up on my recommended list last year. I read the blurb for it and thought , eh, sounds pretty good. At first I thought it was just a story about a bunch of Romans tramping through central Europe. Then I found I was mistaken. Again it's basically war from a grunts point of view. Good stuff! After I posted my review of Tales of the Seventh, I got a package in the mail. It was a signed copy from Mr. Edelheit with some added swag (giant mouse pad, some bookmarks and stuff. And an invitation to be on his beta reader team. Reading is awesome! Swag from the authors is awesome too!