My nomad 55 1X12" has been in the studio and on the road for 3 years. In that time it has been in for service twice, new tubes once and power transformer issues once. Personally I have had to open the amp up to fix pots 4 times.
My biggest gripe is the pots and the front panel. The nobs are...
My Nomad 55 had a huge hum on channel 3 (set for hi gain) The service tech told me the transformer had come unmounted and some other more technical problems with power handling. We changed tubes and made a makeshift fastener for the transformer. Expensive, but it worked.