Some minor things, but overall it´s good Puntuado con 5 de 5 estrellas
Ok, i´ve tried and it works better than i expected. It finds the lyrics of music in english almost all the time, but when i play videos in spanish (my native language, so those are the one i search the most) it usually need a second or third click to find the proper one (in rare ocassions it won´t find it at all); that´s not so bad i guess, it´s cool that it gives you the google link, so im fine with that. I´ll try to sort the available lyrics sources from the configuration to see if i can have better results.
On the other hand, it has some minor things with the visual desing, for example when the title of the video is longer than the floating panel width, the caracters try to rearrange themselfs in a new row, but the title height wont increase so this new next row fonts looks cut, and ugly. Instead it should put a "..." when the title wont fit.
Then you have the icon that appears in the right upper corner of the youtube page, why there? why no under the video next to its info? other Add-on put their buttons there and you dont have to move the cursor trough the whole screen to reach the upper right corner.
And the fact that i have to go to your page to change the options it´s just weird (why not an icon in my firefox toolbar?, and from there a right click or something).Other than that it does what it says in a very cool way, i definitly going to stay with it. Thanks.
Re-order the sources to get lyrics more quickly
If you get lyrics at the third click only, you should definitely try to re-order the sources. Put the source which works best for you on top. If lyrics can still not be found, just point me to a site which provides excellent lyrics in your language.
EDIT: Check out version 3.4.2, it contains fixes for the visual issues you've reported, and full support for Grooveshark!