I think Sam summed it up nicely overall, from a reality standpoint.
The SKS is a decent rifle, but its not an AK.
While it seems some think the mag is a detriment, its really not. You can load/unload/reload the gun quickly, safely, and without fumbling. Something not said for the SKS. I can pop a mag in an AK without chambering a round, and lock the selector, and the gun is "safe". It can be quickly charged if needed, or quickly unloaded if needed, without fiddling.
The mags also keep your ammo secure, and easily accessed. My experience with the SKS and strippers, has not been as positive, especially if you draw the strippers from a chest bag or pouch. The strippers tend to be poorly made, and dont retain the cartridges well, and more often than not, you dont get the full ten rounds in the gun. If they havent already left rounds in the pouch when you try and draw them, they often drop them on the way to the gun.
As far as speed of reloading, theres no way the SKS is quicker. First and foremost, you have to load the SKS three times to equal one mag of the AK's, so youre already behind. Reloading the AK is much more positive and with less fumbling. A quick "top off" is also a lot easier.
"Most" of the SKS's with aftermarket extended mags Ive shot, were not very reliable. Im not saying all of them dont work, but that wasnt my experience. I have shot one of the SKS's with the "factory" AK mag conversions, and it seems to be the way to go, if you insist on a high cap SKS.
Accuracy wise, I never really saw much of a difference. With both, the ammo itself is usually more of an issue than the guns themselves, and with ammo they like, both are more than capable of decent accuracy.
One thing Ive never seen for the SKS was a good way to mount optics. The AK's have a couple of decent options, and you can either cowitness your irons to the optic, or they can be removed and replaced without loss of zero if needed.