Not easy to say from specs: the One X+ camera is 8M smaller pixels and a slower lens, the One is 4.3M larger pixels and a faster lens (in the context of photography, "slower" means "narrower maximum aperture" i.e. less light to the sensor in low light conditions or when focussing).
But there's always more to it - sensor capabilities, lens quality and the image processing algorithms. So as I say, you can't tell from the spec sheets. We need to wait until proper tests are available. My own guess, from what I've seen, is that you might get marginally less detail if you pixel peep (zoom to full resolution of the camera), but will probably get a nicer image at camera or computer screen resolution. It then also depends on what independent developers can do with it (if you are into rooting and modding).
I'd think that for most purposes, unless you like to zoom in as far as you can go, the One's images will be better. But like everyone we only have a few samples to work on, and no controlled comparisons.
)
.... I mean, really. I want a better camera than my 3VO, but am under no illusion that a phone can take the place of a point and click... Seems like I'm going to be happy with it. 
