I cant tell you how many years I've been hearing this. Wasnt Vista supposed to be almost instant?
My boss' Vostro was inexplicably hanging on logout/login, that seems to have corrected itself after a few forced reboots. (And I've had that experience a few times on all OS's, including OS X.) Actually, I can't remember it for Linux, but Ubuntu is much less careful about shutting down gracefully than Mac/Windows.
* I've had four failures to wake from sleep due to low battery in a 2 month span I was dealing with an old battery that was failing.
Power draw in "hybrid sleep" is negligible (less than the idle power draw of my 2 LCD monitors in sleep mode).