I've recently found myself essentially addicted to Alfred Coppel's The Burning Mountain: A Novel of the Invasion of Japan. In this alternate history, the Trinity nuclear bomb test was a failure, which prompts the Allies to go forward with "Operation Downfall", the amphibious invasion planned for a few months after the war ended in real life.
What sets it apart is that it glosses over Operation Olympic (the invasion of Kyushu) and begins at the start of Operation Coronet (the invasion of Honshu via the Kanto Plain), and that it's got an even split between Allied and Japanese viewpoint characters. Among others, some of the notable personages I've encountered are a US marine born and raised in Japan, an Imperial Army Air Corps flight instructor who finally gets the chance to see his enemy in a combat mission, a bombardier from a B-17 that bailed out behind enemy lines, and an IJA corporal who's at the end of his rope after spending fourteen days with two other men in a two-by three meter cavity of earth. The characters express a wide array of emotions regarding their enemies - horror at Imperial cruelties from the Americans, anger at the ruination of their homeland on the part of the Japanese - but these are presented entirely within the confines of the characters' minds and delivered without commentary. Atop all that are the soldiers' personal insecurities and struggles, which often command them above any notion of military duty.
I could gush about this book for hours if pressed. But if you're a fan of World War II's Pacific Theater and have even a passing interest in what might've been, I'd reckon it's a must-read.