I've tested the most known email marketing providers and ended up with Moosend. Their UI is so easy to use and it took me 5 minutes to create my first campaign. I had everything i needed, segments, automations, design tool, and they do have a live, friendly customer support.
We ve been using moosend for the past 4 years and had great results! Not to mention the real time time support that is there every time we have a question.
I trust this service provider, I have been using it to send my email newsletters to my database of recipients for quite some time. They have a strict procedure for onboarding new senders, that excludes unsolicited emails and spam.