It's a great addon; it does what it says on the box.

I saw someone rate the addon 1 star because apparently it hides functionality behind a paywall - er, not if all you want is a convenient way to keep an eye on how many new emails you have, and a convenient, one-click way to open your inbox. In that case, it's free and convenient and does what it says it does.

I can't see how somebody would rationally rate this a 1-star app. I rated it 4/5 as I did just have to reinstall it after it spontaneously decided to stop working. A 1-2 minute reinstall has it working at 100% again.