Personally, I think I may stick with GB for now, as it feels just as snappy as Liberty 1.5. At least, until I get well and truly sick of blur. (Hopefully there'll be a lightning fast, blurless, GB based Liberty ROM to switch to by that time?)
There are a few things that work well for me on this leak, such as app tray categories. I used to use ADW launcher partly for that, but I like GB's implementation a bit better.
Some others, like profiles, only work because I can pick a blank one and configure my screens the way I want them, without having to remove all widgets and shortcuts one by one. (Now, if someone could just show me how to delete entire profiles to get rid of the stock screen setup all at once I'll be greatful...)
Ont the other hand, there is the new blur. It is a little better, at least until you try to use it. I hate the 3D flip animations they seem to have added to everything. The rest of the OS is pretty snappy, but it feels like swimming in molasses when you try to use the social widget, for example. I used to like to social widget in froyo, at least until I installed Liberty and got used to using tweetdeck, but this feels like a pointless new feature that can't be turned off anywhere.