Es malo como todos los que he visto hasta ahora, excepto S3 aunque este esta muy recargado.

Disables the mouse selection, the translation is mediocre, the UI too, not developed in 3 years, don't bother

not work in right click

It's quite adequate, seems to have a large selection of languages. Whether it uses Google or not is irrelevant I guess, but that's why I chose it.
Correction
(I originally stated): Unfortunately, I really wish it did entire pages on the fly, instead of what you paste in the box.
The page I was on, for whatever reason wouldn't auto inject the translate bubble, and I really thought the add-on wouldn't work for me at all BUT once you go into options and change it to context menu then it's readily available. So keep that in mind before you decide to drop this add-on which I almost did
/Correction
Great job, Karl. Many thanks.

Excelente :)

It doesn't work inside Google Docs and Sheets, the icon inside Mozilla's panel is working badly

Отлично, то что искал очень давно и нашел то что искал.

very useful

Lo malo que tiene es que no se puede acomodar el recuadro de traducción en el lugar que uno lo desea poner

jeszcze nic nie przetłumaczył bo się nie otwierał