Neither can do Dolby Vision from discs. The Xbox supports Dolby Vision, just not on UHD discs yet. PS5 has no Dolby Vision (or Atmos) support.
The Xbox player UI is much better than the PS5s. Other than that they're about the same.
If they unlock Dolby Vision support for discs on the Series X (right now it's just streaming apps), it'd be the better of the two.