The SA cycles flawlessly, 100% of the time and is very accurate. I don't have iron sights on the SL8, but find, even with a scope, the accuracy is inferior to the SA. The SL8 has the heavy barrel over the SA, but if you're only shooting semi-auto, what difference does it make? I used my SA Black Special (non-target version) to qualify easily on a 300yd range with iron sights and factory ammo. Didn't the SL8 have some cracking problem in the receiver? Don't get me wrong - the SL8 is a great rifle and its up there on my list of favourite rifles - BUT - if I had to get rid of one, I'd give up the SL8. Thats coming from a bench with bench rests.
If I were using the rifle in the bush or in tactical competitions I would choose the SL8. IMO, it has better balance, easier to shoulder and can support itself better in the prone position with no other support devices. From your original post, the SL8 might be a better rifle for you. Have you considered the Tavor? You would have the added benefit of using the LAR 10 rnd pistol mags. All it needs is a better scope. Shooting in the prone position is a piece of cake with this rifle - it supports itself, so easily.