Weve got a 100 dafs all with astronic, and what they have learnt is annual gearbox oil changes are literally worth their weight in gold, daf say 3yr or 300k and after 3yrs its as black as can be, after 1yr its still green/yellow depending on oil but is darker obviously.
I like dafs a lot but wouldnt buy one myself, in fact they are my choice of truck to spanner all day long no dramas.
On the upside the clutchs last forever unless the driver spends way to long in turtle mode or is so crap at reversing the clutch overheat warning comes up on the dash 