I've been looking for a good alternative to the as-of-now-defunct "Down Them All!" downloader which is not yet supported by the new Firefox Quantum. Nothing I tried came even close to meeting my demands.... except for this.
All Downloader Professional is exactly that -- a very professional downloader that can literally download all you throw at it. For my purposes it's not as easy to use as Down Them All! but on the other hand it does give me a bit more flexibility and even some added functionality. So far, I really like this downloader.
I would give this a 6 out of 5 stars if I could.