Rocguy said:
I guess I forgot to mention I will be using these on my 6D. Thanks for all the info so far.
A longer focal length for a macro means you do not have to get so close, this allows the subject to be naturally illuminated without shadows from a lens 2 inches away. Since the 50mm is not a true macro, it likely does not focus as closely.
Personally, 100mm is the minimum I'd want to use for macro on FF, and longer is better. If you are taking casual images, the IS of the Canon L really helps, it works far better than I ever expected, I can get close and still not use a tripod and macro head. Don't overlook some of the other third party macro lenses, there are lots of very good ones.
On a crop camera, 50mm might be a good choice, but there again, on a crop body, the Canon 60mm Macro has a lot going for it.