I have been using the free transactional email system from Brevo since february 2023. It's perfect for my use case (around 1500 messages monthly), and have almost zero complaints about delivering issues. Today I made my first paid campaign and really liked it! The template builder is great, and I was able to create my campaign email in minutes. They have a very professional and responsive abuse department also. Everytime I received spam/phishing emails from abusive customers, the issue was solved promptly. 100% recommended!