The biggest problem with PTO generators is the lack of regulation, your voltage and frequency can wander a lot as different loads come on and go off. Your electronic products don't like that, and something's will just fail. The biggest plus to using the tractor is that you use it more often, so the engine gets run, whereas many gensets sit too long and then balk when you need them. I have a Pto unit, and a Lincoln Ranger generator welder. I weld fairly often, so the machine gets used more, and it will power my well, electric water heater, etc. It saved the day after Hurricane Sandy. Having a PTO generator is much better than having no generator, and we don't have that many power outages around here, so I can't justify the cost of an automatic setup.
Jerry