I was concerned with the privacy issue of Gmail at first but the convenience has won. I think quite many people simply go for convenience rather than being "enthralled" just like using Google search. That said, quite many people including me are worried about relying too much on the services provided by Google and giving too much information to them, too.
As for convenience, we can have both POP and IMAP access on a single Gmail account. We can have our mail on our main machines in this way. As an alternative, I think we can keep copies of each retrieved mail on the local folder through mail client setting, too. As for checking mail on the move, people concerned with privacy would prefer VPN, though. The important thing is that there are options available and we can choose our own ways depending on our needs.