it free for teams which send low levels of emails, has a good number of ways to connect to your app just like Mandrill. For me the main issue was pricing. Mandrill suddenly started kicking out free customers and I needed something similar and SparkPost was the best alternative that I could find.
FREE – 100,000 Emails/month – $0.00 /month
PRO – 100,000+ Emails/month – $24.99 /month
SUPER PRO – 1 Million+ Emails/month – $199.99 /month