Something that is a little more expensive is
R-max. In my area , it's $10/sheet vs $7/sheet for OSB. But one side of it is foil so it reflects light very well. It also weighs next to nothing so installing it by yourself is a snap. Since it's foam it is waterproof,so if you happen to get a roof leak it wont be affected/rotted by the water.
Just a thought.
^^^This stuff USED to be super cheap. Like, $3/sheet. Darn petroleum prices raised the price,though.
It's what I used in my shop. I love it. Foil duct tape the seams and you have a air tight ceiling. It's obviously not a very strong material,but it will support the weight of insulation when you get around to that point. I hung mine with
Button Caps about 12-14 years ago and it hasn't moved a bit.