Oilers fan here. JJ has shown he's an elite PK'er the last couple years, but won't give much 5v5. Great teammate though, and will drop the gloves to defend teammates consistently.
The biggest challenge for him has been consistency - he's shown flashes where he's been a really good third line forward, but that's been derailed mostly due to injuries. He was playing quite well for a stretch this season and then had two concussions in a pretty short span, and didn't look like himself for the rest of the season when he did return.