I just discovered today that a standard Salesforce field "Other Address" (on the Contact object) is not mapped during initial deployment by default and that there is no way to map standard fields retroactively after initial deployment. Support was not able to tell me why this is the case OR what other fields also do not sync - only that "yes, some other fields" in SFDC work the same way.
While I'd really like a solution... I REALLY want to see some documentation from Marketo about which fields are affected. And this should be availble to potential customers too, since it sounds like the suggested work around will take some time and effort on the SFDC side.
This is related to this idea: https://community.marketo.com/marketoideadetail?id=08750000000I2xzAAC