The only thing that seems difficult is when starting a new campaign, it is not easy to select a saved template and then go directly to the next step which is selecting contacts. This is the only setback that I have personally encountered.
I had only used Gmail and Outlook to send email campaigns before. My member count grew and Gmail had a 100 email per day limit and Outlook was 50 per email. This was not a good solution to sending emails to a group of around 900 members. I found SendinBlue on a Google search and was impressed before I ever bought the paid version.