They're variable and competitive on price from reading articles from Phil. It's going to be interesting, but I'm guessing they won't be a lot more than 50 bucks more. Not sure if PS5 can pull off 400 or not, but if it's 450 then MS will probably be ok at 500 unless they really want to hit Sony and pay for it.
I saw they don't have a optical audio jack and Phil was saying that it's about cost/reward, so you gotta know they're trying to keep prices down a lot.