The best replacement for mailchimp is constant contact.

The best alternatives to mailchimp are rated as following:
★★★★★  constant contact
★★★★★  aweber
★★★  campaign monitor
★★  icontact
★★  vertical response
★★  mad mimi
★★  emma
★  getresponse
★  sendgrid
★  mandrill
★  feedburner
★  infusionsoft
  exacttarget
  wysija
  hubspot
  myemma
  marketo
  mailgun
  constantcontact
  phplist

Your alternative for mailchimp is not listed? Suggest!
Speaking about mailchimp, one probably shouldn't forget about salesforce.

Other search terms related to mailchimp and their ratings are:
★★★★★ salesforce
★★★★★ attachments
★★★★ google analytics
★★★★ shopify
★★★ contact form 7
★ surveymonkey
You have in mind a companion for mailchimp and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of mailchimp in all years. Click on graph for more.
mailchimp
constant contact
aweber