I am also considering an SL-8 or the swiss arms. I am also considering quotes from different dealers.
I already own a AR but as long as it is restricted not much you can do other than punching paper. AR15 does has lots of accessories since it has been exist for almost 50 years.
Here is what I observed:
SL-8: Price wise is more reasonably priced. I see it sold for around USD 2200 in the states. Up here they are sold for about CAD2300. It is also a moderner design that use polymer instead of metal. As long as it is a sport rifle converted from an assult rifle (G36) reliability should not be an issue, but in addition it get a even better barrel (heavy barrel) and/ or perhaps a better trigger, in this case. Also tones of aftermarket parts. (Stocks, forearm, sights etc) but still as many as AR and a bit pricey due to availability. But still available.
Modern = cheap. Any time you trade steel for metal is a step backwards in my opinion. I'd take a G3 over a G36 any day of the week.
The HK SL8 is no slouch however. My only gripe with it is that it is a bulky firearm. Very lightweight and bulky.
Swiss arms:
Design is a bit out dated in my point of view (designed in the 70's). Overpriced. I can see the SIG 556 sell for ~ USD 1700 in US. I still cannot be convinced that the black special worth double. Perhaps I missed something here. Also not as modular as the HK. For the good side is, for the price you pay you don't need to upgrade the stock, the flash hider/ muzzle break, also come with a bi-pod. Looks like it has less accessories either.
I believe they are both reliable and accurate. I am still collecting information on these 2 B.R., if I miss something please let me know.
The SG 556 is an American made abomination of the real Swiss made SG 550. And the Swiss Arms is not overpriced. The price for it is the same in Switzerland as it is here.
What your paying for is high quality materials and production.
Finish: ceramic-reinforced enamel coat known as Ilaflon.
Materials: The receiver and gas system are made of steel. The barrel, bolt, bolt carrier, and firing pin are all made with steel that has been gas nitrided, hardened and tempered. The bolt and carrier, along with most other components internal to the receiver undergo a phosphating process.
Quality control: Swiss Made. Does not leave the factory untill it shoots 24 shots into 4.3"X2.8" at 300m with Swiss Match ammo.
Reliability: AK stlye gas system. 30,000 round barrel life. 100,000+ rounds for all major components.
I'm not too sure about not being modular. You can get railed forends, telescoping folding stocks, scope rails, cheek rests, trigger upgrade kits, brass catchers, forened attachable rails, etc.
I don't think the design is outdated. The AR-15 was designed in the 1960's, and nobody's complaining about that. Why fix something that not broken? There is a reason they are still being made today.