You’ll probably like Robert Buettner’s Orphanage.
It’s in the same vein as Starship Troopers, in that it’s about a young man who joins up to fight against the alien menace, but the real story isn’t about the combat; it’s about Jason Wander’s progression from snot-nosed little shit to man.
I’m tempted to say that it’s nearly Starship Troopers’ equal, but I’m afraid RAH’s ghost might show up with a circle of Martians to make me cease to exist.
It’s an excellent book; I heartily recommend it.
*The book, obviously.