I think it's an awesome question.
Mars has a weaker magnetic field, and that probably means that its ionosphere is effected more by solar wind than ours is. So I don't think it would be very similar to earth, propagation-wise. Probably worse. Maybe like ours is in the middle of the worst solar flare/solar storm/radio black-out ever.
I have wondered this myself. Is there any way to tell whether Mars (or other planets) actually have an ionosphere? Venus doesn't have a magnetic field at all, and is closer to the sun, so it would be getting clobbered by the solar wind, but does it have an ionosphere? I do know that Jupiter has auroras, so VHF propagation would be possible, plus lots of satellites for JSJ (Jupiter-Satellite-Jupiter) QSOs like our EME.