Well put.cliclismo said:I've got a '10 El Mar (blue) and have ridden the KM and own a CrossCheck. Overall the quality on the Salsa is a bit better (lighter tubes, cleaner welds).
I think it really depends on what you want to do with it. The El Mar is versatile but in an off road only sense.
The KM is more "all round" in that it'll take fenders, rim brakes, racks, etc ...
If you want to set it up SS, my vote is for the EL Mar, the dropouts are excellent.