Console -> PC game ports. They are plagued by two problems: Very unstable and prone to crashing, and their UIs are horrible and not optimized for the PC.
Mass Effect was an exception, as it did a fantastic job of changing the UI to match the platform, and everything felt intuitive. Fallout 3 did absolutely nothing to distinguish itself from the 360 version, and as a result feels very clunky and unpleasant to use (seriously, the 'You're SPECIAL' book in the tutorial literally says at the end 'Press A to continue' except you have to click on the A.)
Despite the quality of these titles, they are the most crash-prone games I've ever played. In 3 months I've had more crashes on these games than I have in 5 years of playing PC exclusive titles (or at least, PC games that were not ports from another platform)