I've been using an add-on called Video Downloader Help for quite a while now and I thought it might be helpful to let others out there in cyberland know what an invaluable asset it's been to me. All my previous Video download tools persistently let me down and caused me no end of frustration. This little bag of tricks always seemed to be on my side in heliping to avoid all the technical and procedural mishaps that can occcur when downloading.
What I always find especially reassuring is the way the very convenient interface allows you to pick and select your preferred formats and quality of playback in custom-mode, as well as a facility for monitoring the rate of progress of your download. Thoroughly recommended as an Add-on For Everybody.