I can pull up maps of Costa Rica by location, Driving directions do not seem to work yet (I think this has to do with not having support outside of the USA yet)
If they get Costa Rica routing that I can really use I'd switch to android in a heartbeat.
As for Caching, I believe when you start navigation it caches the info needed for that route.
That would be nice. The mobile internet connections here are really slow and very spotty but if it could do some caching it might be serviceable.