that is what I did.
It worked, and quickly! :-)
It is easy for me, I only have to pay for a SAS licence.
Much more difficult for others who have someone-else paying and providing the hardware and desktop environment ;-) where they want proof-of-value and measured migration timetables and guarantees of compatability and integration and all that stuff ..
4.3 is good
worth the struggle to overcome "management" problems