I can't really compare IEMs to On-ears. But yes, bass alone, the Onkyos simply just does it better, extension with a good amount of rumble. Not basshead, but it goes in there deep.
As I said, the M500 is more analytical but that still hasn't stopped me from walking around the city with them on for the better part of an entire day. As eric said, these things are very comfortable, isolation is a little lacking, but I find that to be fine as these are more of a "urban" portable headphone. Only times I had to take them off was when I had to speak with someone. I think I might have found my portable city-roaming rig already.