The SCAR man, hands down. This is an FN forum though, I don't know what other answer you'd expect to get. So clearly you're looking for a justification to spend the extra dough.
Lets put it this way, the SCAR won a military contract because of its reliability, it has tons of upgrade options, and it's generally an excellent weapon. Chrome lined barrel = quality and durability. You'll wind up with a 2000 dollar weapon in 30 years, instead of a 500 dollar gun that used to be a 2000 dollar weapon in 30 years.