There's some examples of him read gap 1/2 in this highlight video. He comes off the ball quickly, gets maybe a half yard or a yard deep and then holds. If the ball goes other direction he sheds and gets in on the tackle.
I like the thought of a veteran NT vs a Rookie NT. The young players take time to develop and you did draft a young NT last year that still has room for development.
Good value on the trade. He's a 5mil cap hit this year, relatively low. Don't think you'll have to extend him.