It looks pretty cool. Being able to text from a computer (and take phone calls to an iPhone) will be nice... and Spotlight looks much better.
Ah, but those silly flat app icons! Looking forward to when Apple regards that design trend as passé, which IMHO it already is....To each his/her own, I guess.
New font throughout the system, too--that seemed interesting. I'm sure we'll all get used to it as a cleaner look. I am up for the change.
Also, it looks like you can at last get to iCloud files via the Finder now, once Yosemite releases.
Edited by Abram K-J, 02 June 2014 - 03:17 PM.