I don't know about the other 5.56 AK's, but Saigas average about 2 MOA, particularly the .223 versions because they have an overly thick barrel. The Saiga .223 is built on the same frame as the 7.62 version, and the barrel outer diameter is the same as the one for the larger round, resulting in a gun that's very overbuilt.
I wouldn't say 2 MOA is "giving up" the accuracy of an AR rifle. Yes, an AR can do dime-sized groups if you get the right ammo in the right AR, but 2 MOA is perfectly fine out to the maximum effective range of 5.56. You have to recognize that this round is only good out to 500 yards if you REALLY stretch it, and at 2 MOA you'd be shooting a 10-inch group at that range, which reliably places it within a man's torso.
If you get a Saiga, the aftermarket mags you want to get are Surefires. These are fully reliable, and even better than the stock mag due to a built-in last-round bolt hold open. The one true drawback to the Saiga is that the bullet guide is located in the magazine (although you can buy a bullet guide kit from Dinzag for $30 and install it), so they need a tiny bit of work to use standard magazines.