The Canon MR14-EX ringflash incorporates Canon's ETTL flash exposure control, but the ring shaped highlights remain (and are just as distracting) as in the days of the old ML-3:
Many folks prefer the MT24-EX twin flash for macro work. It's much more flexible than the MR14, but requires more set up time and really needs some form of diffusor on the flash heads to avoid blown highlights on every specularly reflective surface. A conventional flash like the 580EX (or even one of the smaller units) will also work well, but needs to be mounted off shoe to avoid shadows from the lens barrel obscuring the subject. These sorts of flash arrangements as well really benefit from a diffusor.
In short, you have a lot of macro flash options with the Canon system, but none are perfect. The MR14 ringflash is very easy to use - set it and forget it - but can create distracting highlights. The MT24 works really well, but needs some messing around with to configure well (and takes up quite a bit of real estate around the front of the lens). The 580EX can be simple enough to use, but requires some arrangement of off shoe cord and bracket which can be a bit ungainly.
Embarrassingly enough I own all three and use the ringflash most of the time just for its size and convenience of use when hiking - even though I know that the MT24 will often give better results when I take the time to use it properly.