The major problem with the PD is that max current is highly dependent on the ac supply. If the peak voltage is not 170V, you will probably get tapering from the start. The Onan microquiet for example does not have a true sine wave. The PD will do poorly with this gen.
Most people now have solar. There's no reason to keep the gen running for hours. In the first hour the Iota provides 20% more charge. That's more than 10 minutes of gen time. I for one hate my gen and minimize run time.
During the second hour the PD gains ground because the Iota drops voltage to 14.2V. If you're never on shore power (like I an), you could increase absorption voltage to 14.3V. The Iota won't lose any ground in the second hour.