You should probably ask this question in the mountain bike forum or over on MTBR.com, but anyway, it seems to me that the obvious difference if you are talking about complete bikes is that the Sawyer has a rigid fork and the El Mariachi has a suspension fork. That one factor alone should decide for you one way or the other. Personally, I'd go for the Salsa and strip the gears and derailleurs and make it a single speed. Rigid is great for some people, but I prefer front suspension myself.