Personal preference. Tube rectifiers are less than ideal rectifiers in that they need to warm up, drop voltage, and drop even more voltage with greater current draw. They also work harder than power tubes so tend to have an even shorter life and fail relatively frequently. The characteristic of dropping more voltage with load is referred to as “voltage sag” and some like how this affects their tone. There are solid state tube rectifier replacements available which mimic many of the tube rectifier characteristics, but not the frequent failure characteristic.
Fat One amplifiers which are based on tube rectifier designs use Weber Copper Cap solid state rectifiers.
