Furring strips usually better for the long run than ply or OSB.
Was a mistake on my house letting them put ply over the roofing boards. I should have gone with my instinct and training.
furring strips here by code, are only required to be 3/4 by 3/4. We've had screws pull right out of the stuff. So we go with 1x6s. cost is a bit more but seems to hold better.