I was looking at one in a local shop recently but was adviced that the fact that you cannot alter the sides independantly means you always get flat lighting. With the Canon ring light you can adjust the two sides to give some shadowing on the subject. If you want to try a cheap ring flash this one's worth a look -
http://www.7dayshop.com/catalog/prod...ucts_id=103779 a homemade difuser on one side could make it a good bit of gear, when I next have some free cash I may well give one a try.