I've installed the development release (downloaded 10th July)on a blog and run the compatibility checker. It reports the memory and object caches are missing (no surprise there - this is a shared hosting account!) but also that PHP Timezone isn't set.
I can't find anything about this in the faq, so what would this affect?
Do either preloading or CDN require the PHP Timezone to be set. (I can ask the hosting company about it if needed, but prefer not to bother them if its not.
(aside: I like that the jss/css stuff is tied to the theme, as I'll probably have to change the theme around a bit - the old theme broke when I upgraded to WP3.0 so I've just set the 2010 theme for now - thanks for making things easier. the auto-discovery of the files is helpful too. :) )