I like that it's easy to send emails from within our application without having any external services involved - we're able get away with using just one provider (Leadersend). The price point could be better but there are some free plans available as well so not too much lost here! That said if sending lots or high value transactions then this does come at cost which makes sense in terms of keeping margins up etc. We have been very happy working through their team who've helped us set everything up correctly when integrating into an existing project environment where things may need tweaking around permissions/etc before they work properly first time round.