Digital Foundry has examined the Xbox One versions of both games and found them generally lacking. Prototype is said to run at 30 frames per second, with occasional dips to the mid-20s. And while it runs at 1080p, it's not as if the game's visuals have been completely overhauled, making it unclear why it doesn't run at 60 FPS. The site calls it "passable in its remastered guise, if a somewhat barebones conversion."
Prototype 2, on the other hand, fares more poorly. DF says it's "among the worst performing games on Xbox One to date," with stutter during cutscenes and a framerate in the 20-25 FPS range while moving around the city. Comparing it with the Xbox 360 version, the frame rate in the Xbox One release is lower in multiple areas. The Xbox One version also has a good deal of screen tearing, something not present on PS3 while still running at a better frame rate.
At best, it looks as if the Xbox One version is fighting to offer an experience on par with that of the last-gen versions, just at a higher resolution--things like texture quality and draw distance haven't been improved.
It's possible the PS4 version handles things better, but that remains to be seen.
In light of this, it's perhaps not a surprise that the Prototype Biohazard Bundle, as it's called, was released so quietly. It's not as if you're getting much of a discount, either--it costs $50 on both Xbox and PS4, though Activision said that it plans to offer each game on its own starting on August 11.