Moosend
We're utilizing Moosend as our ESP for transactional and batch sends, soon to be behavioral triggers as well. I find the platform easy to use and flexible when it comes to real-life use, allowing us clear access to configuration for testing, delivery control, and workflow management. I would highly recommend it as an ESP for mid-cap and up businesses, it is not a small business platform. Overall it makes our internal workflows smoother and reduces time needed for internal reviews. (https://moosend.com/)