It's zip sheathing, so a step above commodity osb.
I also went through a lot of paint
Ah, makes sense on it being a better grade to come out looking like that with only paint. I am a cheapskate so I bought regular grade 1/2" OSB used for framing (very low cost). I think I "paid" for the modest savings in terms of sweat, paint, and fumes! Probably the coarser grade absorbs even more paint. My initial primer coverage was awful.


