I’ve looked at a lot of these services built atop SES (including Sendy), but the main problem that you still seem to have to spend a lot of time accounting for is not getting marked as spam by clients like Gmail. There are things you can do to help stop this, but it takes a lot of manual intervention.

In any event, it’s good stuff like this exists. I would actually be curious to know how many email newsletter services that aren’t one of the big players (Mail Chimp, Adobe, Constant Contact, etc) aren’t just built on SES.