I have the same Arsenal SGL21.
I'm not sure if its exactly the same as yours, but looks very similar to the pic. it is a great AK, and is worth more than any of my AR's. I have a PA red dot on it, and it shoots very accurate, better than a milspec AR, but I didn't do extensive testing, just from my limited experience. it is super reliable, never had a malfunction ever for the several years that I've had it, although I don't shoot it that much. also, I've never disassembled and cleaned the bolt and it still works great. a short description of this AK would be: super ultra reliable, good accuracy, very durable
I've also had a WASR but sold it. never had a problem with it either, but I didn't want 2 AK's and I like the Arsenal better so I sold the WASR
both are very reliable and durable.
I think a big reason why people say AK's are inaccurate is bc of the crappy iron sights that come with it. maybe with practice it gets better, but compared to a red dot the factory irons are not nearly as good, IMO
overall I like AR's better
I've built a few in different calibers, but mostly 556. I built one in 7.62x39 and one in 308. which is one reason I like AR better. you can build them easier, modify, upgrade, different calibers, parts are easy to find (although not right now due to covid19)
I like building and modifying things, so the AR is a great platform for this. AK you can do the same, but just more info and more parts for AR, or at least seems that way to me
You reminded me of another thing about my AK.
I bought expensive, authentic Circle-10 30-rd mags. Had no problems function checking them all.
At KHSC, a guy came up to my bench as I was shooting the AK. He'd just bought an AK and some other brand 30-rd mags. He was having a misfeed every 1.2,3 or 4 rounds. He asked if I'd try his mag in my rifle.
Mag functioned perfectly through 3 x 5-rd reloads. Shows that some rifles just aren't as compatible with certain mag brands/models. Also true with certain "flavors" of ammo.
That little test gave me an even higher opinion of this AK's reliability.
I also let him use a Circle-10 mag in his rifle. No malfunctions at all. So, now he has to do some experimenting to find what mags in his price range work in his rifle. Not a position I'd like to be in when the outcome might mean life or death.
I view firearms like I view other products I may one day need to save my life. It just has to work. Saving a few bucks here or there isn't worth the chance it may fail in a pinch.