It is barely more useful than the default spell checker. What I wanted from this is an auto-detect for auto-switching languages. It hasn't implemented it. It also doesn't show the squiggly lines and is quite buggy.

But above all, it uploads every keystroke to its corporate servers... So... uninstall immediately, how bloated and intrusive is that? No thank you, either take all the code to the client add-on or don't make a spelling add-on at all....