There are many different mail clients for Mac OS Sierra, that have features that are useful and not useful. Mail clients for Max OS Sierra are very common app that people use to try to organize all of their different emails into one single mail client for Mac. In summary your “Top 5 Email Client For Linux, Mac OS X, and Windows Users” is nothing but a fly-over “busy-work” bunch of useless filler, (besides all the errors and omissions). The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. The email client needs to be compatible with Microsoft Exchange 2010. Looking for an email client for MAC OS X, which does not include the native apple email client, and does not include the following: Outlook for MAC, Airmail, Sparrow, Thunderbird, Foxmail. OS X mail app and all famous apps including Outlook 2011 for Mac don't support Active Exchange, but TouchDown adds Active Exchange to OS X. It provides Mac Users with push email against ActiveSync enabled servers. TouchDown® for Mac is the very first ActiveSync enabled desktop client for the Mac OS/X platform.