Instant IMAP email app for Android

A

AC Question

As it stands, I'm currently using an iPhone 7 and I really like it. However I also have an S7 Edge that was just replaced and brand new. For work, I need to have constant email access and one problem that I am finding is that I can't find an email program that allows instant IMAP push.

I currently use Spark on my iPhone as it allows for calendar invite acceptance as well as instant email retrieval for my work account. On my S7 Edge I have not been as lucky. I have used Outlook which allowed instant email but the calendar invites and event invites would be blank and not properly sync with my calendar on the phone. I also tried Samsung Focus but t only retrieved emails every 15 minutes which is unacceptable.

Are there any suggestions to combat this?