[Belphemur]

I used them at the previous company I worked. They were just launching their products.

They have the best support I ever encountered, we were having weird delivery issue on some specific clients and they help us debug the whole problem.

They have more than fair pricing and actually do a manual verification when you want to start using them (and not just testing with your own domain).

Their hobbyist tier is 100 mails per month. No credit card required.