I kind of agree with Smokey that from a technical standpoint, the backhand is better. The preparation being the main point here. The forehand has slight stability issues.
From an execution standpoint, he has no major problems on either wing. He's blasting winners very handily.
I feel like that's a common thing. From my personal experience my backhand is very technical, had to take a lot of hours worth of lessons to get it right, whereas my forehand I just figured out from hitting it a lot, so I personally can do it very well, it just doesn't look technical.