The best replacement for phpmailer is swiftmailer.

The best alternatives to phpmailer are rated as following:
★★★★★  swiftmailer
★★★★  pear mail
★★  phpmailer lite
★★  sendmail
★★  php mail
★  zend_mail
★  mail function
★  mail php
  swift mailer

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

Other search terms related to phpmailer and their ratings are:
★★★★★ smtp
★★★ amazon ses
★ file attachment
You have in mind a companion for phpmailer and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of phpmailer in all years. Click on graph for more.
phpmailer
swiftmailer
pear mail