Rated 4 out of 5 stars

Pretty nice. It is basic, yet offers pretty much everything you will probably need (i.e. without frills and useless features to bulk it up). It saves me from installing and running a separate package such as Rainlendar.
Only request: I wish there was a bigger, clearer version of the calendar, maybe with a better indication of the day "contents" than just colouring. And if that was done, an extra button option to add to the toolbar to display this larger calendar (because the Windows XP calendar sucks to browse months and years).
I still give it a 4 out of 5 right now, because it does what it says on the tin, and I can't fault it on its current features.

This review is for a previous version of the add-on (1.7).