In my case, as soon as the forum gets proper email notifications, containing the body of the reply, I’ll be all set. I can deal with the other caveats of forum software as long as I can get new posts and post followups pushed through email that don’t require me to click to see the content.
There’s two things that make email superior:
1.-Due to its push nature, you get everything automatically, sorted through the rules you’ve set-up, ready waiting for you in a program you usually have opened (I wouldn’t be surprised if webmail-based users found forum software exactly the same as mailing lists, really).
2.-Offline archive and composing means that if you’re offline or your pipeline is otherwise occupied you can still browse, search and even answer or compose mails and responses and they’ll be sent out whenever. The queue and transmission happen, if you will, in a different thread.
For the second point, searching old posts would also qualify, but I admit that I search always first on the web (and usually find results from the list, which I then chase and reply to, if I had missed the first time around), but for many a massive offline archive is a good thing to have.
So: Please make email notifications right. Include the full text of the post (including quoted text) and make it east to reply from the email, if necessary. 