Very useful and really simple. The best solution for context translation for firefox. But, dear developer, can you see "xtranslate" add-on for chromium and make some functions like there? For example, possibility of choose the other translation engine - bing or yandex. Sometimes other services have a better quality of translation and switch between is really good option. Also make better formatting for source text is can be cool. I really hope that extension will be better and better in future.

I also think you deserve to be a recommended extension. Try writing Mozilla with this sentence by providing the source code. =)