Rated 3 out of 5 stars
Since Thunderbird's notification popup feature is broken in Windows 10, this seemed like an ideal solution, and it works... sort of. Even though the configuration has an option for how many incoming emails to combine into a single notification, the extension spits out one notification for every single email received, no matter how high that number is set. So if in a single polling on an IMAP server, there are 4 new emails, it'll send 4 separate notifications and notification sounds in a row via Win10's notification service.
I love the idea, but until it works properly, I've got to disable it. Getting a whole bunch of notification chimes in rapid succession is too disruptive.
(Review is based on behavior of GNotifier 1.10.5 in Thunderbird 52.2 on Windows 10x64 Pro)