bhall41: I'm thinking the El Primero can handle mid cognac, burgundy, dark brown (which I think is stock right?) really well plus all sorts of NATO, Bund, Raptor, Azodi etc fun straps to boot. The JLC MUT can handle black (stock), grey, navy. That's a really great range to cover with just 2 watches. You are really only missing a light honey brown. I remember gdl recommended a honey brown with the MUT, and oisin just now w brown (im assuming dark). I'll tell you my wife got me a midbrown/cognac strap for my bday and I returned it because I wasn't 100% about it--the black just looked better. I'm still thinking a dark brown would look good too, just havent gotten around to it.
Just my 0.02, navy padded croc with contrast stitching for the El Primero looks nice in my mind's eye.