so far so good. i put one of the last developer releases onto my macbook pro last thursday and have been happily using the new os x release since then. i had meant to do a clean install, but accidentally did an install over the top of tiger, and it works like a champ, honestly.
performance seems really good — most things are snappier than with 10.4 (i think). lots of little upgrades that make things better — smarter finder windows, better wireless UI, stuff like that.
the visual redesigns are driving me a little bit crazy — in particular all the stuff where they’re showing off new effects. the sort-of-but-not-really-translucent menu bar is driving me a little bit crazy, but the translucent menus everywhere are the most annoying thing in the whole system — i just don’t understand why anyone thinks that’s a good idea. they’re not super-translucent, but enough so that the stuff behind them really impacts legibility of menu choices. it’s a bummer.
the new dock is mostly just silly. shadows & reflections everywhere. shiny effects, but mostly distracting, honestly.
calendar has been pretty completely reworked, and it’s a much more refined look now. i’m finding it not quite as readable as it used to be because there’s no active calendar notion anymore (where the appointments would be dark color backgrounds with bold white text) but just the active item. but on the whole, better.
mail has gotten a lot better, i think. more refined visually, although still with the icky lozenge buttons. you can drag top level folders around in the sidebar now, which is much better. there’s an activity display that tells you what’s happening on the network now (very helpful). i like the RSS subscription capability — i’ve subscribed to a small number of feeds that i treat more like my e-mail workflow, and it’s working great, although html display doesn’t seem to be working. for me, the jury is out on To Dos and Notes. we’ll see. data detectors are neat (they give context menus on things like phone numbers & addresses, but are a little subtle for me — i keep forgetting they’re there.
i’m unsure about time machine yet. backed up over the weekend, but don’t have enough incrementals to know whether i like the user interface or not yet. (early best guess: i think they’ve done an admirable job in making backup easy to understand, but their tools are miserable for actually finding something you’ve lost.)
coverflow is visually stunning, and basically useless. not just in itunes, but everywhere, in my opinion.
i’ll have more thoughts before too long. but for now, seems like a good upgrade — doesn’t yet feel like a completely new OS. feels decidedly incremental, although i think that will start to change as new applications get released from 3rd party developers using things like Core Animation.
i also think, fwiw, that the user interface on the Mac is both good and starting to get a little bit confused. toolbars are incredibly inconsistent, even from one Apple application to another, let alone 3rd parties. i think it’s going to get a lot more jumbled for a while, as developers start to throw in HUDs and animations for everything, and as we start to get more and more direct manipulation with rich media types. (in the coverflow view of the new finder, for example, you can flip through the pages of PDFs, play movies, etc.) i have a feeling there’s going to be a large amount of experimentation with new styles of interaction now. i think, also, that it’s going to be influenced more & more by flingable interactions like on the iPhone.
anyway, so far so good.