The only thing I find disappointing in Mafia III is the game randomly crashing back to the Desktop screen for nothing, even when it's played with the Cheat Happens trainer. Though the game is patched now, I'm still not sure the game supports multi-GPU setups or not and whether the game will still crash for nothing at all.
Maybe you should wait for the game's story expansion DLCs be released first and see if they're terrible as the base game is.
If you're still getting crashes to desktop try setting VSYNC to off that should fix it for you.