The RAF endorsed a multi-million upgrade to Blue Parrot (Buccaneer) near the end of its life to raise the System MTBF from 3.5 hours to around 6, which they deemed acceptable. At the same time the superb Blue Fox (SHAR 1, and more akin to Foxhunter) System MTBF was just over 30 hours and considered excellent by the RN.
Not a fair comparison given they were generations apart in technology and decades apart in terms of service. The Parrot update was primarily to one LRU; the rest of the system was on the upward leg of the bath tub curve. That said, Parrot reliability went up after 3rd line was given to Industry. In terms of reliability, Blue Parrot and MCS from the F4 seemed to be on a par but both were 2nd hand from the RN.
MAINJAFAD hit the nail on the head about the influence of the techies on the kit, sometimes it was a matter of taking some short term pain to get everything well in spec, to get a long term benefit. But you can only do that if you have a spares buffer.