I'm a long term user of RSS too, through Thunderbird of all things. My one beef with it, is that it seems terribly inefficient, that potentially millions of client will poll the resources "to check if there's something new". Potentially hundreds or thousands of requests per user, per day. It'd be a lot nicer if it was subscription based, since the content-provider knows when there's something new, they can then push it to their subscribers when it is relevant (and do other neat things like slower rollout to avoid congestion and bad user experience).

It'd be kinda neat if email clients natively supported digesting RSS feeds sent as email, presenting the same user-experience, but without the polling.