This plugin does what it says, so no problem there. However it issues a popup that does get annoying if the visitor is using Firefox with certain settings enabled. In my initial tests the popup to say the cookies were enabled appeared every time I refreshed the page.
I have not yet tried it in Internet explorer as this is a sufficient problem to warrant both further investigation and possible removal.
The chances are that if someone is coming to your site with firefox and has the same settings I do they will not stay long. I SUSPECT (but could be wrong) its because I have blocked 3rd party cookies but then my site uses no 3rd party cookies as far as I know, except for this plugin
There are ways to comply with EU law without a popup and even if that changes then there must be ways to achieve the desired result without having this problem. No it is not an option to enable 3rd party cookies for me since I believe a well written plugin would have forseen this eventuality