I send out monthly email newsletters for my Realtor clients and have used iContact (years ago), MailChimp and ConstantContact. I find the CC product to be the best though it’s clearly not the cheapest. They do have live support though which I like and the emails always look professional. I had problems with MailChimp’s support – not responsive enough and too time consuming trying to describe some issues by Chat or even Email – and I also discovered that if you have email addresses in one particular group and you want to add them into another group, that was considered yet another contact! So I stopped using MailChimp.