I've never patched the game once, and never had any problems with it. Odd.

me too, didn't patched and was unable to finish it
got stuck, errors and stuff

One person's "OMG SO BROKEN" is another person's mild glitch. Everyone's different.

I've played Morrowind, Oblivion, Skyrim, Fallout 3 and Fallout: New Vegas for hundreds of hours a piece and never felt like I had even one significant bug. Other people insist you constantly trip over bugs in those games. Who knows.

On my current New Vegas playthrough:
- One character fell into a rock wall (Super Mario movie style ; ) - I had to turn the collisions off to talk to her.
- Veronica refused to start her quest, totally ignoring triggers I was showing to her. Had to start the quest using console commands, from there it went perfectly.
- Killed roboscorpions in Big Empty tended to stuck in their death animations.
Nothing major and hard to fix, but with Steam I'm sure the game is up to date and should be as bugfree as ever...

The good thing with bethesda's engine games is that you can bypass nearly any bugs except crashes using the console. With Bloodlines that is not the case.