Wouldn't know, in all honesty I skipped the ARMA series and sticked with OFP till DayZ.
I've so far tested the mission editor and done the arsenal missions. One arsenal mission got bugged out, but other than that everything has been fine.
Looking at the patch lists there have been a lot of fixes implemented, so I'd bet that it's now in a much better state than years ago. (come to think of it, this might have been one reason I decided to stick with OFP back then instead of getting a ArmaII straight away)