Java apps seem a bit faster, that's for sure.
Some criticisms...
Installation destination dropdown box - the entries are a bit small - hard to press with fingers - also the destinations are too dark (dark grey on mine) - hard to read on a black background.
D-pad still missing diagonal keys - non-touch games are still a little unplayable.
Haven't had a chance to look at it's features yet (JSR-256 support?), but I'll have a look soon enough.
Red.
Edit: Orientation changes are now instantaneous (don't know if that's anything to do with the phone being recently hard reset due to a v20-v21 upgrade), but a MASSIVE improvement over the built in JVM's 5 seconds to switch orientations.