I like the templates and the ability to bulk email, as well as partner it with pardot for SMS automation. I have also really enjoyed the Mogli team and their willingness and ability to create solutions that work for us.
Logged communication within Salesforce of all incoming and outgoing messages (with who sent them). The ability to build workflows to send off text messages or even capture information in a text conversation to create leads is super! Customer Support with Mogli is top notch. Usually issues are resolved within the hour after submitting a request.