I stumbled across Brandon Ness while looking for sci-fi with a military edge a few years back. I was deep in a 'Starship Troopers' and 'The Forever War' reread phase and his stuff popped up in a forum thread about overlooked authors. He's not a household name, which is a shame because 'The Aethereal War' duology really clicked for me—it's got this bleak, grind of a war against an unknowable alien threat, but the focus is less on the big battles and more on the soldiers trying to hold a line when command has no clue what they're doing. The tech feels grounded, which I appreciate.
He also wrote a standalone called 'Chrome Tide' that's more cyberpunk than military SF. That one's a neon-drenched corporate espionage thriller about data runners. It's faster paced than his war books, but keeps that same focus on characters operating in systems that are actively hostile to them. I remember the ending left things a bit open, almost like he planned a sequel that never happened. If you're into that genre mash-up, it's worth tracking down a used copy.