Still on 4.3.3 - I could just not live without retina, scrollingboard, 5 rows keyboard and mainly xbmc. And I would greatly miss the bt gps stack and others.
If the jb stops being an option in the future and Apple keeps their garden closed, I can see an significant migration pf users from ios to Android devices.
I bought my very first apple product (ipod touch 3g) only after learning about the jb. Otherwise I had not bought it al all.