I will give you an example of how good the SLCs are. At 2300-2500 yards I found a lone cow elk in a clearcut that was dotted with tree stumps by the color difference alone. In a handheld mode using a shooting stick to steady them I could not verify that the thing I was seeing had legs and was actaully an elk but the color was certainly elk color and nto the color of the stumps. It was striking enough to get me to run for the spotting scope. With a spotting scope and the Night force rifle scope I was able to verify that it was indeed an elk and had no antlers.
In other words the color transmission is extraordinarily good. Resolution of fine detail at those ranges with it not on a tripod is problematic. I am sure Michael is correct that the ELs are better but as he says how good do you need and how good can you afford.