Sit and Smile

It's great. The blank template is the most newsletter-y template to use. Which i love. It keeps it simple.

Great, super easy to use. You can do pop up or in-line forms, create custom meta fields for the information you want to collect. And it's quick and easy for people to fill in.

Really helpful customer service. And you are able to embed the calendar in "custom liquid" section of your website page so that a calendar is visible to your customers.