I like Mixmax's interface; it seems very clear and easy to use. The automation feature is particularly helpful as it allows me to enter people into sequences, which automates the outreach and takes tasks off my plate. This means I don't have to worry about it running in the background, making my workflow much more manageable. On the individual user end, connecting Mixmax to my Gmail account was fairly straightforward and simple.

scheduling out emails, being able to ensure I'm not sending emails to folks already currently engaged by me/ someone else on my team

Seeing when people open my emails, especially how many times