Re: I'm having a Windows XP moment here..
10.6 (Snow Leopard) was a bit of a brown bag to be honest with the move to x86_64 pretty hamfisted. Some of the bugs have still not been properly ironed out: my system will pause for a couple of seconds every time Time Machine fires up the external (Firewire) drive. It never did that in Leopard. Lots of drivers were broken and some got broken in the series. Can't remember exactly when but Bluetooth audio got totally fucked and the only solution was to upgrade.
While I understand the basic rationale behind the release cycle (cleaning up the toolchain) and simplifying patch levels, a key part of it is creating obsolescence by somewhat randomly declaring certain hardware no longer supported. So my MacMini (x86_64 capable) can't be updated because Apple and or nVidia won't update the drivers. I assume another generation of hardware will get the chop with 10.10 so that owners can go out and buy some new kit. If they're really lucky they'll have to get new peripherals as well: quite a few manufacturers don't support Mavericks. Fortunately, this is one of things that Windows VMs are good for, so I can still use my Canon scanner the odd times I need to.
The notification centre is okay with most things disabled. Pity you can't disable the fecking Finder messages!