« on: April 30, 2013, 05:08:36 PM »
I have not used the Sigma, but did own the Canon 180L. It is a tremendous lens with great IQ, but heavy to handhold for an extended period of time. Ideal for tripod/studio work, but without IS/OS, it has its limitations in the wild.
I sold it and purchased the 100L, primarilly due to teh HIS feature. Sure I need to get a bit closer to the subject, but overall, I am happy with the change.
I would push you toward the Canon because the L glass keeps great resell value.