I've been using this service for a while. It works well. It's not perfect IMO, but I don't know of any other services which are as good as it.

The main thing that I dislike, is that it is obvious that I am using Postmatic to anyone commenting on my site. The emails you receive from it are in a very particular style. I'd like just an extremely crude/simple text email with no advertising or branding in it. KISS (keep it simple stupid).

I'd also like it to be self-hosted to avoid privacy issues.