Correction for CA

Of the many different lens distortions, I found CA the most annoying and the most difficult to correct. I have a 5D and a 24-105. CA often happens at unexpected places. It can be as wide as 5-6 pixels at the edge of the frame. I have CS2 but I found the CA correction tool unsatisfactory. If I reduce the CA at one place, it is often at the expense of worse CA somewhere else. The resolution of fine features also suffers. Is there a better tool or technique which can give better results? Any suggestions? Sorry I do not have the means to post some examples.

Thanks,

Shii