If a contact lives in a unit or other type of building that has more than just a street number, TomTom Go just reports that it can't find the address. I can't figure out what annotation to use, and seeing as I'm having it look up contacts I don't want to remove the finer details of someone's address from my contacts entry. It means I have to duplicate my contacts list in to My Places (but with unit / building / apartment / lot numbers etc) removed from the address.
And with business addresses, if there's not an exact match it doesn't offer alternates. I find quite often a businesses postal address is different from what TomTom will accept as the postal street number is different from that listed in navigation systems.
Contacts, even now you can finally search it, seems quite poorly implemented and not thought through that much.