What is the best YouTube to MP3 Converter?

I frequently use http://convert2mp3.net/en/ for online conversion or Freeware converter. For the latter, I haven't used the software in awhile. However, when I was using it, compression and the rate of conversion were customizable for most outputs. I've heard it has gone full ads though, so I would research into it before concluding to download it.

- iA