I donated way back when this was being developed. I'm happy I did, because I've used it ever since. There are other downloaders I have tried, but I still keep staying with DWHelper (DownloadHelper). It has continued developing and updating through the years. Lots of conversion options. Use their own downloader, or your browser to download a file.
One thing I am missing, is how to download a large video file (movie) when it is broken up into hundred of small files.