[l33tfr4gg3r]

I'm on a 2013 MBP and I upgraded to Yosemite yesterday. It was a textbook upgrade for me - zero hassle and everything works just as it should (so far anyway). A couple of quirks I've noticed vs. Mavericks is that a) the animations seem to stutter sometimes - I almost never had that with Mavericks. Perhaps since this is 10.10.0 that's to be expected but hope they fix that to buttery smooth in the performance update down the road. The other thing is RAM usage seems to have gone up significantly. I used to average around 2-3 GB used out of 8GB and now I find 5GB used - I haven't installed any additional software or tweaked any configuration settings - this is purely a Mavericks --> Yosemite in-place upgrade. Its still early hours so I've yet to explore the system fully, but apart from these 2 things it seems fairly solid so far. Contrary to the other comments, I don't quite seem to mind the full screen mechanics, although I would not have minded a '+' button and more discernible buttons in general.

[dan1234]

I find that Spotlight tends to do a complete reindex after an OS update, so that may be the cause of your increased resource usage.

[saturdaysaint]

I saw a lot of glitches immediately after updating, but am getting buttery smooth performance now, so this is worth keeping in mind.

[l33tfr4gg3r]

Interesting, thanks. I guess I'll monitor this over the next day or two.

[Stubb]

Probably real smooth due to the widespread beta and Yosemite being almost entirely visual tweaks and better integration with iOS devices. Those things shouldn't cause trouble.

Apple seems to have given up on core upgrades addressing performance, the ancient filesystem, and needs of power users after 10.6. And there’s still stuff that I could do on a NeXT in the early ‘90s that OS X can’t do.

[jmcdowell]

What sort of things do you miss? Never got to use NeXT so purely from a 'seeing what I'm missing' point of view.