Hi Rob,
I have one. I had a major pain in the bum trying to get it working, as it was sucking in too much air initially. They do get a lot of bad press but, since I overcame the problem I had with mine, its worked fine. It now hangs on the side of my sump underneath the main tank of my Rio 180. There are better skimmers out there, there are worse ones too.
Its not too bad for noise. If you run it at full pelt you can hear it, but then again you don't really want to be running it full power because of microbubbles and you'll be skimming water off mainly.
They are reasonably efficient and do remove a fair bit of gunk from your water in a short space of time. There is very little that can go wrong with them, aside from somehow cracking them or if the pump failed, Other than that, they are pretty much ok.