Evidently I don't enjoy military science fiction, and have wasted an evening and early morning on a book series I'm going to discard. John Ringo's Posleen war, to be specific.
I suppose I should have given up once the premise -- Eaglelanders to the Rescue IN SPACE! -- became clear, but I enjoyed Stargate SG-1 and it was more or less that. This one has a number of distinct issues which Stargate did not.
For one thing, military protocol is hella boring. It's fairly lightly represented in Stargate. The U.S. Air Force wasn't the only valid perspective at the table, and I was not suffocated with infodumps and acronyms for things which are there just to prove the writing is authentic.
Secondly, every member of the human species and a whole universe full of hyper-intelligent technically advanced aliens are utter idiots, save of course the protagonists. Who all seem to spend their time sighing, face-palming, and generally being vexed. Even the enemy is pretty much a collection of faceless mooks who suck at life.
Lastly, I don't believe the premise. A intergalactic network of naturally pacifistic races turning to humanity as proxies against another hostile race of semi-incompetent lizard people bent on invading Earth for some reason is fine, I suppose. Although the idea of various species evolving without an ounce of aggression seems highly improbable -- even herbivores have mean streaks when pressed. Rather, It's just too convenient by far to believe mankind will suddenly become competent participants in an interstellar war in a matter of months. The level of adaptability the humans express towards their situation is staggering. He makes a point of having his badasses act all banal when meeting the aliens for the first time. Mind you this is set in the early 2000's.
More generally, I don't think conventional military wisdom is applicable in interstellar terms. For one thing, I don't see the specific need for ground forces in a genocidal war, which is what the book is pretty much about. Even with powered armoured units it doesn't make much sense. It'd be far easier just to do a colony drop. The idea of plundering worlds for resources is pretty stupid too, unless I'm vastly, vastly, vastly underestimating the scope and size of the universe and the potential for extracting resources from it efficiently. Unobtainium does not exists, much less underneath the Earth.