I am totally blown away by this. This is (IMHO) exactly what Windows mobile has been waiting for.
I have downloaded and am using this on my HTC TyTN II (Kaiser) – works like a dream, very easy to use and responsive to finger touch / navigation.
There are a number of known issues with it and some reports of it not being great on devices without touch screens, but run (seriously, run very quickly) over there and grab a copy.
It is still in beta and the guys at Pointui have made it free (paypal donation optional). Unfortunately it does not cover all apps and aspects of the Windows Mobile UI, but the parts they have covered off are stunning – when these folks get all the common apps covered (Contacts, Dialer, Mail etc) then it will be incredible!
I love the list of known issues they have on the release announcement on their forums – it includes : Not enough time in the day and Red Bull wearing off – classy.