What do you use for targeted emailing?

While building Yuma, I was using mixpanel to track user events/actions and with that segmenting users and sending data-driven emails. But it seems there's no more emailing functionality.

I moved to customer.io later with credit, but it's clunky, not so great UI, and expensive.

All I want is a simple way to track user events/actions and send targeted emails. Any suggestions or am I going to have to build it myself?