UPDATE (later, the same day):
1.) I've also tested iPad Video Converter for Mac by 4Media (current version: 6.5; $35.99; discussed for example HERE). It was decidedly faster than the previously-discussed, in no way recommended converters: converted the first three minutes (that is, 30.1%) of the Buck Bunny video in 4:35. That is, it would have converted the entire video in about 14:40. However, while it's faster than the apps in the same price segment, I still don't recommend it: after all, why spend $36 on an app that is still slower and less supported than HandBrake?