I'm about 25 hours into AC:V (PC) and the only crash I've had so far is just when I initially started it, which made my computer reboot for some reason (possibly outdated drivers).. but after that, no crashes. A big handful of (mostly hilarious) bugs (wile-E-coyote type stuff, or silly ragdolls), but that's it. It's pretty decent, gives me some light Red Dead vibes with how alive the world feels. Side missions are more often just quick encounters, which is nice. Good voice acting. Gorgeous map. Good performance. Great, gory animations/finishers.
Only issues I have with the game is that they cram in puzzles almost everywhere, for simple loot, and it gets tedious. Mostly mean this just for getting the golden chests with resources and such, sometimes it's just not worth the hassle. Combat's really fun though, once you get a bunch of abilities unlocked.
Watch Dogs felt like shit though. Only played for an hour or two before I uninstalled it... Cool city, but it feels REALLY damn arcade-y. I like the ideas they had, and you have a little more freedom, but actually running around or getting into combat feels like a poorly made indie game that doesn't take itself serious. Numerous bugs, too, like fist-fighting an enemy and the enemy stumbles backwards inside the wall, so it pulls out a gun and proceeds to shoot me from behind a solid wall. I loved WD 1, and hated #2, but I believe these games need a bit more weighted reality to it. #2 is where it started to get ridiculous.