GMX has been rated 4.3 on Google Play. Pay attention to the important detail: advertisements are a part of this application and it offers in-app purchases. The app is often downloaded by Samsung and HTC users.
It's free to get the .apk file of GMX and you can take a look at users' reviews on Droid Informer. This application installation package requires 18 MB of free space on your device.
As users state, the app features some important pluses, they are a simple and clean interface, great performance and advanced features. The way users see it, this application has the following drawbacks: login errors, too many ads, annoying notifications and a battery drain.