Unobtrusive unlike the other YT downloaders, and easy to use. The converter is awesome. One of my favourite add-ons.

My only complaint is that due to the generic name, it's hard to find this plugin when installing a new browser. I've written down RayLo to save the useless trial-and-error plugin installations.

Note: not using FFx57... will let the early adopters deal with the inevitable plugin bugs. To the Dev, keep up the good work--it's appreciated.