Good

VDH has been great up until the 7.3.9 release. It then started behaving bad, as in starting, but never completing video downloads in linux. I tracked this stopping to a build with a library(GLIBC) version that is ahead of many linux distributions. Researching in Google, VDH personnel are claiming that it is not their problem and are doing nothing. GLIBCs normally work if the program build is on a lower version than the distribution. It seems like VDH only needs to build using an earlier GLIBC version.
4/17/20 update -- I checked a windows version and I get the same strange behavior of hanging in the middle of a download forever. Manually stopping it in windows, unlike linux, does not result in any error message.
5/9/20 Loaded up Coapp 1.5 and tested again. Did not work any better. Still getting the same errors(below) and only ".parts" of warying sizes.
Errors:
Exit code: 1
/usr/local/net.downloadhelper.coapp-1.5.0/converter/build/linux/64/ffprobe: /lib64/libm.so.6: version `GLIBC_2.27' not found (required by /usr/local/net.downloadhelper.coapp-1.5.0/converter/build/linux/64/libavfilter.so.7)
/usr/local/net.downloadhelper.coapp-1.5.0/converter/build/linux/64/ffprobe: /lib64/libc.so.6: version `GLIBC_2.27' not found (required by /usr/local/net.downloadhelper.coapp-1.5.0/converter/build/linux/64/libavformat.so.58)
/usr/local/net.downloadhelper.coapp-1.5.0/converter/build/linux/64/ffprobe: /lib64/libm.so.6: version `GLIBC_2.27' not found (required by /usr/local/net.downloadhelper.coapp-1.5.0/converter/build/linux/64/libavcodec.so.58)

I am truly happy to have come across such wonderful software!

it is very good

If you don't need to convert videos, and I usually don't, this is a great add-in. Yes, it requires you to pay for the conversion part - but I've never needed that bit; I use it to save videos from YouTube that fellow crafters have made and I do recommend this addin.

Changed from a useful app to a cash grab. Uninstalling.

muito bom

Después de horas descargando un video para quitarle el ruido y poder oir bien la conferencia resulta que te pone una marca de agua y ahora lo que no puedo hacer es verlo bien. Vaya perdida de tiempo...
Además es incomodo de usar.

flashgot was my all time favorite download addon, but firefox new architecture killed it (for sure to much efforts to implement. i still was happy, cause this time was spend to noscript, an other project from the creator of flashgot).
then this video downloadhelper addon was heavily promoted on firefox addon website, even if it was just a dim light compared with its bright predecessor. i installed it cause for lack of alternatives and most of the time, it did its job, even if it had sometimes issues and wasnt as compfy as flashgot.
and now it demands money (30$/20€) to remove a watermark, that itself has encoded in the downloaded video.
the new art of blackmailing! time to move on..

1.) This is not a complete app—it requires another "companion app" in order to function. This other app is not available through the Firefox extensions page and requests more access permissions. If I were a computer programmer/app developer, I could perhaps review for myself the source code for specific evidence of nefariousness, but I am not.

2.) I would have given 2 stars, but the .mp4s I was able to download were corrupted. Downloading and converting at the same time requires the companion app, and another, third app, as well. I will not be downloading two further apps from a website I don't know just because of the presence of this half-functional app on the Firefox extensions page.

Hence, 1 star, and uninstalling.

works great. easiest way to download. works for video and audio

Love it! Last one did not work. I rate it 4 stars because you need a whole 'nother app for it to run and downloads take a long time. But it's better than nothing!

Davvero comodo

Muito bom.

Muita facilidade e praticidade para usar! Me ajuda muito !

Sehr guter Downloader

goodd

Very easy to use; excellent add-on