Sometimes
1) doesn't scale well. The amount of work just to get Ubuntu into a usable shape is increasing per release. I can't tell you the number of hours I've pissed out of the window on it over the last few years. It's the equivalent hack status of Windows now which removes every competitive advantage I have by using it to start with.
2) There are no explicit benefits to using Ubuntu other than you probably already have it. The benefits are disppearing faster as to be honest it's not really a fairly compatible Linux distribution. There are Ubuntu-isms creeping into other things and this is seriously bad news. Canonical just want their slice like the Unix vendors in the 1990's.