[joachim]

If you shoot mostly portrait, FF makes more sense IMO.

 

Now, if AF accuracy for is your main concern, you should consider mirrorless instead. AF accuracy is much more reliable and accurate than any DSLR. If portrait is what you're after, you should strongly consider Fuji (the 56 f1.2 and 90 f2 are fantastic portrait lenses).

Another vote for mirrorless here if AF accuracy is a concern. 

 

Fuji cameras and lenses are very tempting.  As I know from my X20, the in camera JPEG engine and in camera editing function is a big time saver.  I am sure the lenses names above are very good.  Unfortunately they are also very expensive.

 

The non-existence of a more economic alternative with fast AF made me stay with Olympus when I last upgraded.  From a price/performance perspective the Oly 45/1.8 must be one of the best buys out there.  As far as I can make out the compromises are poly-carb outer shell (have yet to see any report on that lens falling apart for that reason) and that it is f/1.8 and not f/1.2.

 

Another aspect is size.  SLRs and the matching lenses are typically on the big site of things.  A smaller mirrorless is less intimidating.