I havn't tried 4.0..
But from what I get its like paying for a mac but not getting OSX..
And compatible with amiga trough UAE?
I'm more compatible trough winUAE under x86 then..
As for os4 A lot has happened since 3.9 and if the a1 ships with a complete linux install what's the point of running a 4.0 on it? KDE or gnome will do the same things but with better support and critical updates.