At first it seemed nice, but it's been getting in the way. At first it passively highlighted problem areas for me to review, but today it's been agressively throwing up dialogs on its own, blocking my work. It also abuses its access to my attention by marking an error but pitching it's paid service when I click on the text. It does have a good dictionary (much better than the native Firefox spell checker) but the gramar engine is stuck on pedantic. It enforces rules that aren't required unless you're writing a formal document. The last straw was when it started trying to autocomplete sentences. Today I typed, "work address:" and it threw my actual work address (and how does it know my real work address?) into the email. I ignored it but the suggestion kept popping up as I edited that part of the email. It ultimately inserted the address by itself, on a blank line, between "work address:" and the address I had already added. It even used a font style that didn't match the surounding text.