Kdenlive is described as 'Intuitive multi-track video editor with robust hardware-accelerated support; offers chroma key, color grading, and extensive audio/video format compatibility' and is a leading Video Editor in the video & movies category. There are more than 100 alternatives to Kdenlive for a variety of platforms, including Windows, Mac, iPhone, Web-based and Android apps. The best Kdenlive alternative is Shotcut, which is both free and Open Source. Other great apps like Kdenlive are OpenShot, DaVinci Resolve, Avidemux and Write-on Video.
ffdiaporama is aimed at making slides with video effects, it's not actually a video editor.