Expect Meta's next headset to adopt many of the Quest Pro's best qualities: the color passthrough cameras and mixed reality capabilities, the smaller lens system and crisper visuals, and on top of that, likely a faster, better processor.

Source: https://www.cnet.com/tech/computing/meta-quest-pro-half-a-year-later-caught-between-quest-2-and-quest-3/

Meta reportedly hasn't refined the display hardware, but the biggest upgrade on the Quest 3 is enhanced support for mixed reality, thanks to the passthrough cameras on the front.

Source: https://www.slashgear.com/1298838/meta-quest-3-boosts-mixed-reality-take-on-apple/

There are Quest Pro-optimized apps that use the color passthrough cameras and mixed reality features (and eye and face tracking) to different effects, but most of these extras feel tacked on, not quite necessary, gimmicky.

Source: https://www.cnet.com/tech/computing/meta-quest-pro-half-a-year-later-caught-between-quest-2-and-quest-3/

“Varjo is the only company currently offering high-fidelity video passthrough technology, similar to what Apple is rumoured to be using,” Timo Toikkanen, Varjo’s CEO says.

Source: https://thenextweb.com/news/apple-rumoured-mixed-reality-headset-miracle-european-xr-industry-needs

Without things like video passthrough, (which we are now finally getting with the “mixed reality” on the Meta Quest 3) or perfect fidelity that helps ou avoid nausea, VR headsets only work for a small part of the population, he said.

Source: https://venturebeat.com/games/finding-game-jobs-and-other-sessions-from-gamesbeat-next-the-deanbeat/