great question. we'd like to. have any ideas for the most inexpensive service? we don't have a business model (and don't plan to serve ads)...we just want to see what happens.
my main gripe with the built-in mail app is that it doesn't thread sent messages in the context of a conversation. also that you can't 'send as' all of the addresses in your gmail. was hoping they'd solve this with the gmail version...but yeah, still quite buggy.