I think a lot goes into it. I am switching equipment for the first time in ages this year and will be able to speak more on it later.
However, I would put a lot of emphasis on whether the player is considered a "feel" player or more of a technical/numbers player. Personally, as a feel player, I will be hesistant when playing with me new stuff for the first time. But, I know I'll get used to them.
For these tour guys, they are so good, it doesn't matter. And a lot of it is all about the $$. So I can't really blame them.
I wish I could type way more but I'll ramble on forever. You pose a very solid quiestion and I think we could get quite the discussion going here.