What is the difference between these two materials and which one is preferred by ARFCOM?

I was looking for a set of TRU-SPEC Multicam BDUs and all appear to be made with 50/50 CORDURA NYCO RIPSTOP.

Cordura is a brand name for a textured nylon fiber.

Cordura is the real deal and probably the best known brand for Nylon.

It's still Tru-Spec.  It's probably gonna fade pretty quick.  I have a set of Tru-Spec multicam and a set of Propper Multicam.  The Propper still looks new the Tru-Spec started fading shortly after getting it.  I'd say after about 3 times wearing it out in the woods and camping.

and that has about every thing to do with the fabric, not 'who made it'

and washing it the correct way helps also.

Correct way as in what the tech info calls for?  Such as proper detergent and what not?

My Propper MARPAT uniforms that I wear everyday unless it's an off day, will last a pretty good while before noticeably fading and I'm pretty sure I'm not washing them per the "regs" as far as proper detergent selection and what not.  I even wash them on the hot setting every now and then to get carbon and grease stains knocked out.  

That's just been my experience though the Tru-Spec (or whoever they acquire their material from) won't last as long as far as coloration and whatnot than the Propper.

cold water
inside out
detergent with OUT optical brightners ( I use woolite dark )
hang dry.

propper uses a different fabric ( for multicam its 65/35 poly/cotton ) and tru-spec use(d) several, mainly 50/50 nyco, and the die takes to the fabric differenty right from the start.

YMMV