It's decent. I knocked out 3 stars because:
1. I cannot add job for indirect downloads, like downloading from google drive, so I cannot set the number of threads before downloading.
2. I cannot increase number of threads during download either.
3. The icon in the toolbar doesn't show sign of activities (i.e. number of current downloads) or changes (i.e. number of completed downloads), something you see in icons of NoScript and uBlock Origin. You have to actually click the TDM icon to see those.