Re: I'm having a Windows XP moment here..
were you aware of the improvements being required before you saw them in each version from 10.6 onwards? In other words, how do you know that 10.10 will be more pain than it's worth?
Good question, and the answers are "yes" and "because we evaluate first". I'm on the side of caution because I use my systems for work, so I too wait a few months before I upgrade a major release (days to weeks for a point release like 10.9.2 to 10.9.3 as they tend to be about security).
By that time I've seen any issues show up online, I will have wandered into a shop and played with it and I will have read through the docs. If that looks like a lot of work, it's simply because change represents risk for a business, and frankly, we did no different when we were still a Microsoft/Linux shop (we're now an OSX/Linux shop with some scatterings of iOS :) ).
We took a conscious, well reasoned business decision to go the Apple route.
For us it works, but it's not an excuse to abandon caution. I like what I've seen so far, even when you peel off the inevitable show gloss (I want to see if it's all that slick in the hands of an unrehearsed end user, for instance), but any sharing feature is a cause for concern. We have obligations to demonstrate compliance with all sorts of rules so until we understand the precise hand off mechanism and have control over it we cannot deploy those new versions of iOS and OSX.
So, it's wait and see for us..