ACYMailing provides everything you need in a Newsletter extension.
It manages subscribers/users, allows you create any number of different lists, allows you to create subscription forms and even a squeeze page if you need one. And provides all the tools you need for creating a great Newsletter.
Support is excellent and timely
I use this extension for managing subscription to our Newsletter.
To create a simple newsletter, the interface is very straight forward and easy to use. If you want to create a newsletter that connects to your calendar, store, Social Media and fires when events are added or new items to the store are added, etc. the you will find the ways to achieve this fully explained and if your are a seasoned developer, you will find their MVC contemplating exactly what you need.
I have been using Joomla for 3 years and during that time I have become well acquainted with templating and template overides and prior to that I was fluent in PHP, JavaScrip/jQuery, HTML and CSS and MySQL.