Our kids saw it yesterday; daughter was a French/Business major, spent lots of time in France, SIL military historian.
They thought Juaquin Phoenix was way too stoic and less charismatic than Napoleon was said to be. His intense love for Josephine and her relative indifference they thought was well depicted. The battles they thought were well done.
The movie was apparently, though, woefully short on info about the muskets used, caliber, projectile weight, powders used, muzzle velocity, and effective range. And there were sabers and bayonets aplenty, but little mention of what steels were used and whether they were ground or forged.
So, most of the important information was left out.