I was having the same constant crashing to desktop that others are reporting.
After just a few minutes of game play, the game would stutter, freeze, while audio continues, then crash to desktop.
Based on a hint someone else said re: a windows log issue, I moved my game install files from the boot SSD to another SSD.
I had Uplay revalidate the files, and have since been playing with no crashes.
Just a suggestion to try, if you have the option of a second hard drive or SSD. Move the game from to another drive separate from your OS.