Fantastic email client that I've used for several years now and wouldn't use anything else. It has a very rich feature set and integrates with many major services like OneDrive.
The only decent email client, and it’s free. The 2.0 email list layout is not as easy to use as the original, but thankfully they give you the option to use the original.
Generally very happy with the app on iPhone. UI could be better on my Mac
Would be nice to adjust font sizes for received messages
Helps me with productivity