As a small erntrepreneur, I was looking at a good and reliable mail tool to track my campaings and transactionnal email.
It is by far the best builder I have used and the team behind it was able to help me on every matters I had during the setup.
Once your domains are set upthe tool is very powerful and you can create campaigns and track leads in details.
Some simple yet very useful things like removing trash contact from a campaign (that came back bounces) allow you to send mails to only target leads over time.
I recommend their tool !