I've been watching the development of the SCAR-H and -17 from the sidelines since it was announced, and have had many opportunities to handle and shoot the rifles. The biggest attractions to the design for me are:
* Reliability
* Lightweight
* Lower receiver ergonomics are good, a la AR15. Selector throw is 45 degrees, and intuitive.
* Accuracy for a mass-produced self-loader seem to be exceptional.
The things that bother me are:
* Overall feel of the gun created by the height above bore of the aiming plane, a result of the operating system
* Butt stock feels like it's a weak point, and cheek weld doesn't feel right to me. 1 Platoon in 3rd Ranger Battalion broke all of their SCAR-L buttstocks within 2 weeks of testing. The cheek piece needs to be coated in elastomer.
I would prefer the top rail to be about .7" lower on this gun, reducing the bulk of the overall system. That would require a complete redesign, but I think the SCAR needs a redesign anyway, for a number of reasons. I'm not one of the types who looks at something NSWC does and then assumes it's good to go, since the Squeals have all kinds of money thrown at them that is used to replace weapons frequently. An enterprising unit could accumulate an impressive array of exotic weaponry, night vision, and commo gear just by aligning their deployment schedule right behind the Squeals, since their accountability of weapons and equipment is atrocious by even pogue standards. Their whole outlook on weapons is, "Who cares, we're going to get replacements as fast as we can spend our grotesquely obese budget anyway." That's why the M60E3 lived so long with the Teams, because they could afford to purchase critical spare parts and new guns ad infinitum, whereas the Marines and Army had nothing but trouble with the M60.
For the Squeals, it's just another short-term adventure to generate photo ops for the Navy so they can recruit young blood who will fail BUDS and end up hot-racking in the fleet with 6 other dudes in a cubicle in the belly of a carrier on 5 and 6 year enlistments, where the Navy really needs them. So the whole "SOCOM-approved" stamp needs to be processed with a filter understanding that a lot of that is with the Teams, and their procurement posture is something that no civilian can sustain when it comes to spare parts and plain old complete replacements of entire weapons. A unique weapon in the hands of a urinalysis-failing Squeal raging on roids makes an awesome poster at the recruiter station or online, but has almost no relevance to someone on a budget looking for quality gear.
If you look at the SCAR, it's basically the modern hybrid interpretation of the Armalite AR16 with a polymer lower receiver modeled after the AR15 (magwell, ergo's), so FN has copied a Stoner design operating system like HK did with the G36, then called it innovation. These are all successful designs, but nothing revolutionary. I still feel like there is a lot of room to grow, and the design finalized represents something evolutionary, rather than something that should have been produced. Since there was so much pressure to get something onto the market and into the SCAR trials, it appears that a prototype was settled on, rather than a fully-matured package.
For civilians, they won't notice or care for the most part, so as long as there are cool pictures of it in the hands of Squeals, and it maintains its reliability and accuracy record, it will remain a favorite among those who can afford the price point.
That said, if I was on the end of a 7.62 NATO logistics chain and wanted a lightweight 7.62 NATO carbine, I would be tempted to grab one myself. The need to use clip-on modern TWS/NV devices in the DM or Sniper role would force me to choose the KAC M110K instead.