From what I have read there doesn't seem to be any visible changes to the legacy desktop.
The main differences since the Consumer Preview seems to be in Metro with lots of new and improved Metro apps and a few tweaks to navigation and multiple screen support.
Not sure if I am going to bother downloading though I suppose I will have to install it on at least one computer as I will have to support customers that get lumbered with it on new computers
The one positive point is that Windows 8 seems to be better optimised and apparently faster than Windows 7 - but to be fair everyone always says that when a new OS is released - give it six months and everyone will be saying why is my computer so slow again.
The one big criticism (apart from the obvious stuff) is that there doesn't seem to be any emphasis in Metro on getting actual work done!!