The rivalry between Mark Zuckerberg and Tim Cook has been going on for years. Here’s what they are fighting about now.

The latest battleground in Apple and Meta’s feud is their work on virtual and augmented reality.

Apple released its Vision Pro headset in February, and Zuckerberg was quick to offer his critique of the competitor to Meta’s Quest headsets.

“I have to say that before this, I expected that Quest would be the better value for most people since it’s really good and like seven times less expensive, but after using [Vision Pro] I don’t just think that Quest is the better value, it’s the better product period,” Zuckerberg said in a video on Threads. “They have different strengths, but overall Quest is better for the vast majority of things that people use mixed reality for.”

Zuckerberg says many people “assumed that Vision Pro would be higher quality because it’s Apple and it costs $3,000 more.”

“I know that some fanboys get upset whenever anyone dares to question if Apple’s going to be the leader in a new category,” he said. “But the reality is that every generation of computing has an open and a closed model. And yeah, in mobile, Apple’s closed model won, but it’s not always that way.”

Meta CTO Andrew Bosworth has also taken shots at Apple over its Vision Pro.

“As soon as I put the headset on, I can see what trade-offs they made and why they made them. And, perhaps definitionally, those aren’t the trade-offs I would have made,” he said.

Bosworth called the Vision Pro’s motion blur “really distracting” and said the headset was “very uncomfortable to use.”