The War With Earth by Leo Frankowski is classic style SF. I grew up on the likes of the Stainless Steel Rat, with a super competent main character (and often a loving wife) outwitting the rest of society. This story is right off that block, with main character being a Soldier in charge of a super battle tank that is powered with by a sentient AI. Working with his wife and other members of his command staff his team thwart both the public (by protecting the secrets of the Kabushian Expeditionary Force) and the Earth invaders.
Things come awfully easily to Mickolai. The opposition is shown as dreadfully incompetent (let's face it, competent can be a pain) and with the aid of the AI's very few things slow him and his team down for long. A neat part of this book is the concept of Dreamworld, where a user linked to the computer can experience things at multiples (17-30 times) real life. Makes basic training or even earning a PhD possible in very short time.
All in all a fun fast read.