JDownloader is a popular tool to accelerate and download any file from any source with a good speed. Also, will help users to organize their downloads by categories or types (music, video etc.).
Is able to download videos, it has browser extensions to run automatically when users are initiating downloads. You can set limits for bandwidth consumption to not consume all available bandwidth, you can pause, resume and restart downloads any time.
Is developed by a German company, it has large number of users, but there are many objections because it includes too aggressive advertisement such as installing toolbars without user consent, so you need to pay attention what you check/uncheck during the installation.
A good equivalent for Windows is Free Download Manager that is free.
