Orphanage by Robert Buettner is an impressively well done Military SciFi! I rated it five stars on GoodReads jokingly asking how could I rate it less considering how I couldn’t set it down! Take short chapters combined with tense action, a fast paced story, then fill it with quality characters, and you get a page turner that’ll keep you up at nights. 
The basic concept is that our world has come under assault by alien invaders and we’re trying to fight back. War makes orphans, and the human race is arming and training those orphans to seek our vengeance. In the midst of seeking that vengeance they might just learn about true family. 

In thinking about comparisons I can see comparisons to Full Metal Jacket, but the book isn’t as dark. It’s more that it follows a similar path of basic training to war in all its confusion. 

One thing that quality Military SciFi needs to have is some form of social commentary and Orphanage has that. It definitely has that, and it adds to the overall story rather than distracting from it. Here’s a book to read, enjoy, ponder, discuss, and then read the sequel!