Very good.

Very useful plugin. What is a "deep search"?

Works perfectly fine when settings were adjusted to what I needed.
There are many websites supporting reverse image search. If you do prefer some and do not like some other, you can change what to use in settings.
Some search engines also provide images that are similar in a way of geometry, style, colors. It is very useful when you want to find not only the same image in higher resolution, but to get related images.