There was another one of these that made it to the top of Product Hunt the other day...I don't remember the name. They didn't disclose on their lander whether or not they handled domain based email though, so I would say this one is at least better described if not actually better.

I get the value proposition, but I wonder if the positive response to this concept on HN & PH is from actual potential customers, or is one of those things that sounds to a technical crowd like a good idea for our less technical friends. I guess I am curious how many people that would need a simple service like this are interested in owning their own domain.