Gtranslate Tab gives you quick access to Google Translate. This is a great application for anyone who uses Google Translate frequently, or who wants to have a way to translate text quickly without having to open a web browser. Gtranslate Tab puts an icon on your Menubar. When you click on that icon, Google Translate will pop-up on a floating, transparent window. You can then type in text and translate it just like you would on the web version. In fact, all the settings that you would normally have access to on the web version are available on this window. Whenever you click somewhere else on your Mac, the window will disappear, and you will have to click on its icon again to re-launch it. But it will remember the text that you were typing and the settings that you had changed, so you won't lose your work if you click somewhere else accidentally.
From the settings window all you can do is change the transparency level. I thought the default level was good enough.
As you may know Google Translate is one of the best machine translation services available. I know that it works well, but I tested it on Gtranslate Tab anyway. I added some English text and then translated it into Russian and Spanish, and both translations were good. I then copied the translated text and pasted it onto a Text Edit file with no problems.