The Unity interface has been notoriously buggy and slow. Canonical write core parts of their OS in Python. All my experience with their software indicates it will be slow.
I don't think the people working there are incompetent, more likely overstretched to breaking point.
Unity on the phone (running on my nexus 4) is blazingly fast. I mean, stupidly fast. Android and iOS feel super laggy compared to it. Particularly Android.
It's fast and stable. Canonical write core parts of their OS in C. All my experience with their software indicates it will be fast.
Even some of their ubuntu one storage engineers know graphics programming well enough to win game programming competitions. They're good, and have copious free time to make this perfect.
I don't think the people working there are incompetent, more likely overstretched to breaking point.