well, i dont know about the differences, because it was my first wm65 rom i used, and i am downgrading right now.
file explorer has a problem with my folder "1st install" on the sd-card. when i scroll down to cab files starting with "t", it looses the sd-card. it is gone... soft reset, tried again, same problem... this is not working for me.
as psy-o-matic, a lot of programs dont work. i can install them, but starting is not possible, such as pocketwit, gpscyclecomputer, etc. and as i got already used to those progs, wm6.1 in the latest version of 14-4-09 is my choice....