Tried Many --- Loving "Mailwise"
I was a long-time user of Enhanced E-Mail, which has now been absorbed by Boxer (nice Exchange app also). I tried and really liked CloudMagic, but had to abandon due to their policy of storing ALL your Exchange Mail in the Cloud... on THEIR servers... not acceptable (they are supposed to update and change).
I've since settled on Mailwise and have been using it steadily on my last phone (GS2 w/CM11) and more recently on my G3. Mailwise provides the best features of all the previously mentioned Exchange Mail apps, as well as syncing Exchange Calendar and Contact info. It also supports multiple accounts (I'm running Gmail, Yahoo, and Exchange) with color-coded notifications (nice touch). As a final bonus, Mailwise also has a method for bypassing standard Exchange Security requirements. This allows you to choose alternative security methods, rather than being forced to use a PIN lock with a short time-out. I'm currently fully linked to my Exchange Server and my phone is secured with the G3's awesome Knock Code Lock and doesn't auto-lock for 30 minutes (unless I use the power button).
Oh... Did I mention Mailwise is completely FREE in the Play Store?!?! --- Give it a try and let me know what you think. Good Luck!