I was under the impression that the situation was reversed. My Gentoo systems have been very stable because I take many of the masked package guidelines seriously (of course not all). Meanwhile you have Arch that changed the default python version to 3 back in October 2010 that hosed a lot of people's systems. Discussion: http://news.ycombinator.com/item?id=1808840 and my favorite quote (there are so many great ones though) from the mess:

20:20 <dash> well that confirms my impression that arch was invented by a bunch of guys who thought gentoo was too stable and easy to use