Thanks a lot for this plugin!
I found a major bug, that it doesn't add "ie" to the body class. For every other browser it works.
The problem is in line 237:
case 'Internet Explorer' : $b = 'ie'; break;
It should be this instead:
case 'MSIE' : $b = 'ie'; break;
So, it's very easy to fix. :)
Otherwise the plugin is great!