I had a few problems importing my list due to file format issues, but their support was very friendly and had imported my list to my account for me, so that quickly became a non-issue. They were also quick to respond when I didn't understand how something worked, which really helped me get on with my emailing. Their free tier is great for getting started, but it lacks detailed reporting. Luckily their paid plans aren't that expensive and it's worth it, even if just for the detailed reports.

One of the best marketing tools I have used

You will have access to dozens of free email templates, and they are all made to be responsive and fit for any device. You can import your lists from any source by uploading your CSV spreadsheet, by pasting it in your contact list, or connecting Campayn with Gmail, Yahoo, or other services.