Generally speaking, Inverter type generators will normally have a low THD. The process sounds a little convoluted, but they produce AC, then rectify it into DC, then invert the DC back into AC. That process virtually eliminates almost all harmful THD on the output of the generator.
Here ya go....and as I suggested on an earlier post....."Generator Bible" website is a great resource....and yes, if you scroll down through their write up, it does say <5% THD for that one. In the specs for that one though, it IS NEUTRAL bonded to the frame, and unless you can remove the bond, you will need to use a transfer switch setup instead of the breaker interlock type that has been talked about so much in this thread. https://generatorbible.com/generators/predator/9500-59188/
I just looked at my Genny https://www.amazon.com/WEN-GN625i-C...1R7/ref=cm_cr_arp_d_product_top?ie=UTF8&th=1A Altough I didn't see it in the written specs, I looked at the generator and below the 240V receiver it says 'floating neutral' So I think I'm good. It worked well on my trial run hooked to my home and no issues.
I'd like to also quote some stats. This Predator states a 90 day warranty. My Wen states a 2 yr warranty. Now I do realize that what it says and I have read some bad reviews about getting that warranty coverage on the Wen.