Hey folks! I'm actually one of our support engineers for our on-prem biz unit, however I came across this post and wanted to post a quick ack on it. Our SP team is working hard on a focused response to the ticket you sent in. In the mean time, we have a blog post that touches specifically on Sparkpost as an alternative to Mandrill, following their announcement:

https://www.sparkpost.com/blog/mandrill-alternative-sparkpos...

In addition, as mentioned by meirelles a few hours ago, the free tier has been raised from 10k/month to 100k as part of a pricing adjustment which was planned prior to yesterday's events.

So stay tuned for more info!

-Codey