LR5 actually picks up some (all?) of your LR4 settings and preferences, except, at least, for your backup preferences.
It took me a while to download it late this afternoon, but the problem was on my desktop machine. My laptop had no problem. Installation on the desktop went smoothly, as did the import of some of the images I wanted to test. I played with the new heal tool, which didn't impress me, and the radial filter, which looks like it may be very useful.
Obviously, I will spend more time with each in the next few weeks.