He'll get lots of offensive rebounds. He's more than big enough, he's just not quite long enough. But it all adds up to a big plus, because of his strength.
There are not many bruisers at PF these days it seems. White is a bruiser with above average athleticism and leaping for a guy that strong.
You know how Lebron bullies his way to the rim with his big strong shoulders? White is like that, but even stronger, if less athletic.
He can totally create his own shot in the post, and he's hardly scratched the surface in that regard. His ball handling is superb and he can get his shot off against any big, usually right at the rim.
His reach is 7 foot or 7'1", so it's exceptionally long for a kid 6'8".
He doesn't seem to have a whole lot of moves in the post, but that was his first year of college game experience, and he's never really had to develop many post moves.
He could be really good, to the point that everybody else is trying to find the next Royce White.
He won't be the fastest, longest, or jumpiest power forward in the league, but he'll be able to get a body on guys and keep them out of the paint. His quickness isn't below average for a PF, and his rebounding is above average. 4 is the position he defends best, and I think he'll be at least average within a couple months.
The only thing I'd look for with him is manipulative tendencies. I haven't seen any of that yet, so that's good. You don't want a guy who's gonna pull the "crazy" card when it's convenient.