I uploaded the stylesheet from 1.5 to my 1.4.5 install in order to use the ready classes. Overall impression: YAY!
However, I have noticed that anything styled with these new classes doesn't have the same left alignment. It seems to be ignoring the form-wide formatting.
My example is at https://web.saumag.edu/admissions/application/
Tested in RockMelt, FF 3.5, IE 7.