Which email app is best and on budget?

[dandelion3]

I am currently researching email apps.: I looked at Mail Chimp, Active Campaign, Drip and Campaign monitor.

Mail Chimp has very competitive pricing and you can buy colume based. What is important to me:

• that I don't need to buy another app to make the email app working fully.
• esay to use, easy to understand,
• automation for: abandoned chart, automation after purchase (3 timely staggered emails after buying), email after signing up... typical things
• how do users react to the mail? - data
• connect what users answer to reviews

What else is important to an online shop?