A lot of things. They got an early reputation as "Bioware's Little Brother" with KotOR 2 and Neverwinter Nights 2. Their QA methodology was horribly archaic up until Dungeon Siege 3. With the exception of Alpha Protocol, which had its own weird set of problems during development, their games suffered huge deadline issues. And they seem to be the major exception to the "super high production values" trend in RPGs lately that we've seen with Bioware, CD Projekt, and Bethesda, which kinda feeds back in to the first thing.
EDIT: Also, they put Chris Avellone in charge of most of the New Vegas DLCs. And while I respect the
out of the man, he has some very strange ideas sometimes.