Macro Ring Flash

I am seriously consider to get a Macro Ring Flash. The original one from Canon costs over $500.00 which is over my budget.However,at e- bay they are selling after market brands for between $70.00 to approx $100.00. Some of the are flash and some of the are continuous lighting. I prefer to have the "flash"version. Since the price difference is so great, what should I be looking at when buying a Macro Ring Light unit?

I bought a Sigma ring flash a few weeks ago for £220 - I promise you, they're not worth the money, I'm returning it. When mounted to the lens as intended, the light the flash produces is utterly flat and does not flatter subjects at all. When held off camera, the results it produces are good, but the same results could be produced by pretty much any flash held off camera and it's simply not worth the money, plus it's very difficult to hold the flash off camera and take a decent photo at the same time. Not to mention it is uncommonly difficult to diffuse!

My advice would be to AVOID ring flashes at all costs, unless you intend to use one for medical purposes or similar. Here's some examples of why I dislike them:

FLASH OFF CAMERA:

I tried a steady burn on some coin and water drop shots, didn't like them,I also tried diffusing with a tissue and it seemed to soften the image.I of course think they may hold some value when used absolutely as intended which I don't know what that is.I being very inexperienced would say go with an off camera flash on a bracket based on what I have been seeing around at different forums,It seems to be the option of choice..

dick