I've had the opportunity to run three campaigns while this is still up on AppSumo. We previously relied on Infusionsoft for some of our outbound emails, and man what a difference!

Pro:
Easy to setup, easy to create a campaign and just go
Support is fantastic! I always get good answers in just a few mins, and I've asked a lot of questions
Open rate in general is very good (around 29%) compare to 22% of Infusionsoft that we used
Works with Zapier so I can get it hooked up to GoToWebinar and remove registered users

Con
The analytics are still a little bare, but you can download all the info including sent time, open time and more to create charts on your own

Overall, the deal is a STEAL. I bought 3 stacks for my team.