It is a nice plugin, and it does what it is supposed to do. There are just some -admittedly idiosyncratic for me- annoyances.
First the end user documentation. It could be better, not all of us admins are familiar with Google's intricacies.
And then there is the insistence of the plugin that I take a tour. I click it away some 2 or 3 times a day. I took the tour, and once is really enough.
Ah, and localization. That would be nice. (I'll send mine for Dutch after I've done it Joost).
Apart from that, it offers good functionality. Even one I haven't found elsewhere, the ability to exclude logged in users, above a specified level.