My 4/4 is a 1981. Very reliable with over 80K miles. I have replaced dash switches, rebuilt rear hydraulic dampers, replaced king pins once, and clutch once.
My 1986 Plus 8 is also reliable except for the electrics. Some of which may be attributable to prior owners. Some of which to Lucas (Distributor.)
My 2005 Roadster appears to be much better built (Things fit better, are straighter, tighter, etc.) but I don't have the experience with the car to ascertain its overall reliability.
All my other Morgans have been rebuilt/restored so the question is not valid.
Cheers,
