(K)ubuntu, mint, manjaro, and a few others I don't remember. I went through a whole slew of them and didn't find one that was stable, not even mint. One of the issues is that problems are intermittent and start without any obvious cause. One day the external monitor works, the next day it doesn't. Etc. This is a huge issue when the problem hits six months after purchase and the only solution is to reinstall. I do remember kubuntu used to be stable back around 2007 or so but that was a different era. In 2010, it made it to about six months before the x wouldn't boot anymore after I changed the title bar color or something like that. On my current iteration on the mbpro, I've gotten about 4 months of use out of it after it failed within the first week. Often just changing something minor like the display manager's wallpaper will kill the entire desktop environment. In no case was there an actual kernel crash. It's always the gui. And it doesn't seem to matter what desktop environment runs. None that I've tried have been stable.