I am a fan of self-hosting, right up until the point it crashes on you and you have to spend a weekend fixing it. You are right, email is one of the biggest headaches out there.
I love it when a CEO participates in online discussions as it is the sign a company that cares. Just one thing about your post... It sounds really defensive. Maybe just me, but all the good will of participating in the conversation was lost. Maybe a "Hi, I'm CEO and love getting feedback. What's wrong with our USPS Calculator?". :)