What are the greatest video downloader programs to collect YouTube videos?

...Without ads, extra installs, and failures...

many sites you can finding to download in different format - just copy paste link, pick format, wait, download.
i using jdownloader though. have to install, but working great and for also file hosting link :)

JDownloader is awesome.
For 1080p, you are required to download ffmpeg.
JDownloader will install it automatically for you and copy the 1080p stream.

Due to YouTube's new policies, 1080p streams can no longer be downloaded without hacks.
JDownloader will copy the downloaded temporary files and recreate it in a new file.

All other resolutions will download as they have been stored on the youtube site.

Grab which ever version you like best.
Youtube stores various formats depending on what browser is being used. Old Flash vs. new HTML5 (experimental).
You can choose MP4 or OGM or even FLV if you want.

OGM/OGG tends to be larger in file size, but MP4 (h264/avc) is more compatible.

DownloadHelper on Firefox is the best one I tried so far.

J-Downloader worked good but it also put junk on your computer.

Free Online YouTube Downloader: Download YouTube Videos, Facebook and many others! (http://en.savefrom.net/)

Keepvid is the most useful I've ever encountered. They've recently made some overhauls, too. Offering a range of qualities and formats for video downloads. KeepVid: Download online videos from Youtube, Vimeo, Twitch.Tv, Facebook, Dailymotion, Youku, Tudou, Metacafe and more! (http://keepvid.com). Not only that, they support many other sites for downloading videos as well, such as Twitch, Vimeo, Dailymotion, Instagram, Vine, CollegeHumor, and many more..

DownloadHelper will go to a newer version and work again within several weeks. Also waiting for Firefox 37.

For a stand alone program I would suggest Free YouTube Download (http://www.dvdvideosoft.com/products/dvd/Free-YouTube-Download.htm#.VRNEGOE3J_k) and the Firefox extension I would suggest is FlashGot (https://flashgot.net/).

I use add-ons for firefox. I used to like download helper but I recently changed over to:
"Download YouTube Videos as MP4" and I really like it. You can search for it at firefoxes add-onsite.

I highly recommend 4K Downloader - https://www.4kdownload.com/products/product-videodownloader

Most of the browser extensions are infested with dodgy spyware so I stopped using them. This standalone app is great. It'll download even the highest quality video, convert to mp3 and more.

Good! Firefox 37 and VideoDownloadHelper 5.0.1 all work together.

My favorite video downloader is called Youtube-dl for Linux it is small, easy to use and can download from just about every video site I have tried. Install the youtube-dl program from your software repos and then all you have to do is open a terminal window and type youtube-dl and then paste the url of the video.

JDownloader has an issue with anything 60fps.
It only does 30fps.

It does 2160p, however.

There are options to get it to grab 2160p@60fps, but don't know why it only downloads at 30fps.
I don't think it's a bug either. I think it's a limitation partly due to Youtube's policies and how they changed their site.

2MB/sec data transfer and integrated to regular downloads. Great!