The mag issue alone has kept me with 5.45

Besides mag prices, the straighter 5.56 is a fussier feeder than 5.45.

There is a nice 200yd highpower experiment where a 5.56 20"bbl VEPR with Black Hills ammo put 7 in 2 3/4". Pushing 1 1/2 moa is nice, but not everyday for skill or budget.

2moa seems to be the wall for good smallbore AKs, but it fortunately can be hit with 10 cent ammo. My 5.56 Saiga and 5.45 Bulgy build both hit 2-2 1/2" as normal good-effort groups, and the Romy 5.45 guns seem 1/2" bigger.    

.223 is more accurate than 5.45 due to the variety of really good .223 ammunition on the market.

5.45 magazines are easier to find and less exspensive.