The one I had ran terrible on gas ignition. It was a bear to start, ran much hotter, and made less power. That said, it ran great on alcohol with spark ignition. Very clean revving, idled great, and made more top end RPM than gas/spark. I never ran it on glow ignition. The owner of MECOA told me that glow was THE way to run these engines.
I never flew mine, it just didn't have the power to weight ratio for anything other than Cubs, Flybabys, Aeroncas, etc. I just can't get into those planes.
It did sound awesome. Imagine a cross between a VW and Continental.