MailDroid has all the features you could want from a mobile email client and it continues to be built around user feedback. With the ability for IMAP users to sync draft mails, sent mail, deleted mail based on when they are on wifi or mobile as well as pop3 preload capability.
MailDroid was built with mobile data in mind from the start. MailDroid also is an email client focusing in on what business users want such as choosing to delete an email locally or from both device and server per email read as well as custom rules to alert and move certain email to folders.
Finally, for the power users there is even encryption capability using openPGP and S/MIME. MailDroid will allow you to encrypt and/or sign email using openPGP in the MIME format or Inline format and allow you to encrypt and/or sign an email using S/MIME. There are so many other features that can be found in the app, please try the ad version to see all.
MailDroid v4.53 Apk