My experience was with the new IQ series not the ix. The biggest difference is in the engine size. It is an 80cc engine where the Honda is a 98.it was not significantly quieter than the Honda except in the low speed. The dB rating is 2 less than the Honda. I found it in a spec sheet deep on the website.
BTW, when I was trying to find out why the 2 of them in parallel would not run my ac I talked to the local service center. He told me that he hated them and they were nothing but trouble. He also said that I'd there was anything wrong with the inverter section it had to be sent off and could take 6 weeks or more.
Chris