It's tricky because resolution on its own doesn't necessarily make for hugely better better image quality, though of course bigger resolution does help.
Lenses, panel type (OLED, LCD, Pentile, etc.) and field of view all make a difference.
For instance the Rift doesn't have a better resolution than the standard Vive, but the lenses have a bigger 'sweet spot', and the panel pixel arrangement means it has less of the 'screen door' effect than the Vive. It also has a slightly narrower FOV, which makes for a slightly larger apparent resolution (more pixels per degree of view), so text tends to be more readable.
So though the Vive Pro is undoubtedly much better than the Vive due to the increased resolution, it isn't as much of a step up from the Rift, especially as it uses the same lenses as the Vive with the smaller sweet spot. (though it is a step up, no doubt about it).
Also supersampling can vastly improve image quality, so if you have a good GPU you can brute-force a better experience.
I'm biased as I'm a Rift owner, but I would go for the Rift over the standard Vive just because the touch controllers are light years ahead of the Vive Wands. Oculus Touch is like having your hands present in VR, while the Vive Wands are like using tools in VR.
Hand presence makes a huge, huge difference, which is why Valve are creating the Knuckles controllers that will make the Vive much better in this regard (when they ever get around to releasing them).
