I was trying to think of what might useful for a lot of Steemit users, and I remembered that at times I'll use CloudFile's Transfer website to download YouTube videos. It's very easy to use, you don't have to install anything, and for cell phones it even works with Chrome for Android, as an example. I'm not sure about other mobile OSes like iOS.
Here's the site: http://new.cloudfile.co/transfer
And these are the steps.
Copy the URL for the YouTube video you want.
Navigate to http://new.cloudfile.co/transfer and in the top left corner, paste the video URL in the field labeled "Simply drag and drop files or Paste URL". You can also paste via the big + button at the bottom of the page.
The site will get your video ready for download, and populate a download instance when things are ready in the middle column of the site. You can create a queue by pasting multiple links in the field mentioned in Step 1, and this will populate multiple download instances you can scroll through.
You can choose to download an audio-only MP3 file in the "Choose MP3 Quality" section, then by following the prompts, or download a video (or M4A audio-only file) via the "Choose video quality" section drop-down menu and pressing the green Download button. There will be multiple resolutions available in MP4 and 3GP formats. You'll see the resolution and file size listed, so choosing will be easy. At the very bottom of the drop down list, you'll see an M4A audio-only selection. I actually recommend this over MP3 if your media player can make use of it. As far as I know, this is audio taken directly from the video with no re-encoding, and won't result in a bit of quality loss like re-encoding to an MP3 file would. But the choice is up to you, of course.
There is also a format converter right below the ripping functions, if you need one. But again, this would necessitate a re-encode, and as mentioned above it's best practice to avoid that if possible.
A final note, you can minimize/expand or delete video download instances by clicking on the respective controls at the top right of each instance, i.e. the up/down arrows and Xs.
And that should be it. I've never used CloudFile for cloud storage, but their Transfer function for downloading YouTube videos is excellent. As stated, when using the green Download button there shouldn't be any quality loss, since as far as I know, there's no re-encoding.
Enjoy!