I don't know why some other reviewers are not happy with this product.
I was also somewhat sceptical looking at the UI and the response from owners to appsumo questions and reviews, but then I decided to give it a try.

So far I was using ActiveCampaign basic 9$ plan for occasionally sending emails to my tiny email list.
(while I was waiting for people at Erxes to improve their Email marketing system.)

I found 366 to be very useful for my use case.
5k contacts and 25k emails are more than what I was getting in the ActiveCampaign basic yearly plan.

Although the platform took me a day to set up, connect my custom domain and put the DKIM keys.
But now, I feel the time was well worth it.

The email designer is another added benefit although I wasn't looking for it.
The support team is quite responsive and I get timely replies.
Email deliverability, tracking and engagement score is also something I like.

Although a con is that it takes more clicks than usual to launch an email campaign, but it doesn't concern me right now.
Yes the UI looks dated but what I care about is the functionality.

Another thing, I asked them for a public roadmap, but they didn't seem to have one right now.
Although there isn't something specific I'm looking for, as what I need is already there.