Mailinblack is great! It's easy to use, very helpful, has many ways of working, and it does not cost too much. There are plenty of features and tools that are available (including an excellent reporting tool), but if you're looking for something in particular, be sure to ask their support team beforehand. I like how easy it is to work with them as well -- it's always nice when companies have good customer service. My current client uses Mailinblack because of its many advantages, such as sending out bulk emails to thousands of people at once from one place.