I haven't had a single spam comment since the moment I installed this plugin (a couple of weeks ago), and I was getting 30+ junk comments a day. I've had no issues with genuine comments (all have come through as expected, and I've tested it successfully myself in Chrome, Opera, Safari and Firefox), and I'm VERY happy with this plugin.
I was getting sick of wading through all the junk, just in case there was a legitimate comment buried somewhere in there, and I did not want to use a captcha, because I agree that spam is not the users problem either.
And now it is no-one's problem! Thank you, thank you, thank you :)