Please forgive me if I missed this in some of the comments and replies, but I saw nothing on Infusionsoft or Marketo. I was expecting to see both in your analysis, but nothing was mentioned, save for the remark early on that Active Campaign has rocketed past Infusionsoft in the marketplace. Is it because you consider them outside the “Email Marketing” space which was the subject of your analysis?
Mailchimp offers a forever free plan which allows you to send 12,000 emails for up to 2,000 subscribers. This plan is fairly limited because you don’t get features like send-time optimization, advanced segmentation, multi-variate testing, etc. You are also required to display their branding in your email. Last but not least, support is restricted to email only which is fine if you’re a hobbyist but as a serious business, you need reliable support that you can count on.