Three different perspectives. Information Week which regurgitates The Christian Science Monitor both of which are refuted by McSolo:
Apple has been more willing to make calculated, graduated, but sometimes disruptive changes to Mac OS X as it progresses. Does Snowy have hiccups? Very, very few. It’s been the easiest upgrade I’ve made since my first venture into OS X in 2001.
Customers downgraded en masse from Windows Vista to XP. Do you see that happening with Mac customers who upgraded to Snow Leopard? No. In other words, Snow Leopard is not Apple’s Vista.