Early RR’s had reliability issues, head gaskets were one of them but they soon got on top of the problems and became a decent engine but like a lot of designs the faults of the first types created a reputation that was hard to shake off.
With regards to the Big J, I never got on with the 220 models, yes they were really good pullers for their class but usually had a poor top speed 45-50 mph and had a terrible throttle linkage (or pump rack?) that would bounce causing kangeroo actions till you took your foot off and replanted it !
Now at Midlands BRS we had quite a few 280 Rolls models and they were real flyers, a lot quieter than the 220 and pulled as well if not better than the 290 ■■■■■■■ models. They were easily distinguishable from the ■■■■■■■ which had the exhaust stack on the R/H side, the Rolls on the L/H.
When big j production finished at Guy’s we had crusaders from there with the same 280 Roller/Fuller set up which were good machines.
Fuel consumption is one thing I don’t really recall but they were certainly no worse than the ■■■■■■■ motor.
Quite a few people on here and drivers I worked with complained about the driving position of the big j’s, I never had a problem and considering I’m no small person I quite liked driving them and was never uncomfortable, unlike the current new Daf I drive !