He is a rookie, so I expect him to get better, he is already way better than the reports that caused him to drop in the draft.
I like that I've seen some heads-up play when he's been out there. Not that there haven't been many bonehead mistakes. But, he makes extra passes, he goes up strong at the right times, he blocks with patience, he doesn't foul nearly as much as I'd expect, he goes up hard for rebounds and often positions well. And his shot doesn't look bad at all.
Also, if you can go by body language, he seems engaged, seems to be an invested team member, and appears to be working. He also doesn't showboat at all, even after dunks and blocks.