Had it done a few years ago - think it was Zoom, but can't remember. It didn't involve any faffing about - just an hour in a dentists chair if i remember right. cost a few hundred quid and results were quite good. I think they had a special offer on. Teeth looking bit yellowy again and now wondering whether to do the same thing again or try a different method. Not massively keen on anything that involves a lot of hassle....