You only need cuteTube2 and the relevant plugins (qyoutube, qdailymotion etc) as required.

I have both at the moment only because I can't be bothered to move the previously downloaded files to the same directory as cuteTube2.

Crash during download I have experienced on certain files, one was a BabyMetal music video but can't remember the others, but usually after download starts. There was a reported issue with audio conversion, not tried it myself.