If the SHTF, I would not want to be relying on a $80 generator.

Been living off-grid for several years. Seen plenty of my neighbors buy entry level stuff that is sure to fail when it is needed most.

I know it's a big chunk more money, the inverter based Honda would be my small generator of choice.

If a UPS system is kicking out when a generator is hooked up to it, my guess would be the generators frequency/voltage is not within high/low spec of what the UPS wants to see. "Dirty Power" is generally a problem with too high/low frequency/voltage. More inclined to show up when the AC source is loaded, not at idle.