They are all safe in electronics. most electronics power supplies have wide voltage and phase plus large filters.

Good thing with conventional generators is that they are easy to maintain plus lots of interchangeable parts. Kung inverter baka walang support, kung masira at walang pyesa matagal-tagal ang downtime mo. I'm running 6yo 7.5Kv China diesel in the house, maingay sya pero may concrete enclosure kaya dampened ang noise. Sa farm i'm using mobile(yung nasa trailer) Perkins with stamford 33KV used to run large motor of tunnel vent. The building gets Johnderee 75KV.. All i can say iba talaga quality ng branded gens.

Regarding KiloVolt rating, IMO when chosing a gen its safe to assume 70% as safe load. Usually 0.8(others have 1) ang PF so kung 10KVA, 8KW ang max load pero bawas pa ng konti around 5.6KW ang safe load. This is useful esp when using inductive load w/c is the common household load (motors of pumps, elevators, compressors) para hindi masira kaagad generator o kukurap-kurap ang output.

Correct me if im wrong pero nalala ko kaya KiloVolt Ampere sa gensets ay dahil sa Alternating Current reactive ang power when loaded merong apparent at real power.. Para lang din antenna you transmit alternating pulse may feedback o energy returned from the absorbing media kaya kelangan mo ng filters.. depende na sa design kung leading o lagging to compensate the type of load - resistive, inductive, capacitive.