Hi, JohnStar! EMUI is a customized "skin" on top of Android on most Huawei phones, like TouchWiz on Samsung phones and Sense UI on HTC phones. It is very popular with some users, and has probably contributed to Huawei's phenomenal growth in some parts of the world. It is also intensely disliked by some other users. Users in both camps have been known to say that it borrows heavily from the iOS interface found on iPhones.
There seems to be general agreement, even among users who dislike EMUI, that it adds some useful features to Android. For those who dislike the interface, it's easy enough to install Google Now or some other launcher and get an experience that's much closer to stock Android, or whatever you want.
Check out the global site for EMUI to learn more about the features - http://emui.huawei.com/en/plugin.php?id=hw_emui_func