I have lost the whole MCP (so no AP, FDs or autothrottle) on a 737 several times, and would have to refer to my logbook as to when and where. I have also dispatched without one, although I can’t remember why!
On the ‘bus or other Boeings, not yet, although I have had an FCU channel fault a few times which is only one failure away from being like a day in the sim.
I hand fly raw data or visually a couple of times a week in conditions (and colleague!) allow; a loss of an AP gives you an aeroplane that is in trim and shouldn’t be any issue at all beyond RVSM and low vis/RNP considerations.
Something like unreliable airspeed or or an uncontained fire cause me far more concern than losing the AP, which is a workload management tool at the end of the day.