Multimedia editing software

The newbie is me, with regard to video editing. I consider myself (mostly) competent in using linux (well, it has been my main OS for about 20 years), but in all that time I have never edited any videos. (I am an expert in image processing, having written two books on the topic, but videos.. that's a whole 'nother issue.)

I am now starting to produce some screencasts, which I'll need to edit: adding some title screens, sometimes speeding up the video (especially for handwritten sections), editing some of the audio... what is my best option for simple, but effective, editing software? I've actually got seven on my system so far: avidemux, cinelerra, flowblade, handbrake, kdenlive, openshot, shotcut. To my inexpert eyes many editors look pretty similar. But I need to choose one and learn to use it. I've discovered that openshot, at least, easily allows me to place a title screen in front of a video. And I couldn't find out how to do that in shotcut.