KDE looks much like Windows (with a start menu). Personally, I don’t prefer that. The taskbar on KDE couldn’t be shrinked much (keeping readability to a sensible level), making it occupy space. The applets on the taskbar, and the menus in the notification tray occupy much space. The new lockscreen KDE 8 also looks much like Windows 10. I like the lock screen of GDM, which slides up like a card and has buttons of just required size. KDE would look great of big displays, but not on small laptop screens. Keep it short and simple). KDE might offer much more features and customization options, but GNOME has a cleaner interface. In day to day use, you might not be using much options.
There may be tons of open source distros, but business matter. People need cash to have food, medicines, house. Most business move around either Ubuntu (Unity, GNOME based), or GNOME (backed by RedHat). This is the main reason most third party applications work seamlessly (are supported) on Ubuntu Unity or GNOME, with lesser hiccups than KDE. KDE is great, but there are other things to care about. KDEConnect is just awesome. It is the best way to get your Android mirror with your computer. One might argue installing it on GNOME, but that requires installing more than 500 MB of KDE libraries on GNOME.