The LX7 is miles ahead of LX5, XZ-2, etc

I can only comment on the LX7 I have, vs. the XZ-2 I have.

The first LX7 I had (for a few hours) had a slightly decentered lens, and the second one I got has a perfect lens.

The XZ-2 I have produces an image that is very sharp in the center, but at wide angle, slightly blurred in the corners; more so on the left hand side.  Maybe the lens is  also a tiny bit decentered, but I am keeping it (the first LX7 I got had a very clear difference between left and right side sharpness).  At longer focal lenghts, the XZ-2 is very very sharp.

So for my application, which includes a lot of outdoors photography at wide angle (hiking, skiing, etc), the LX7 is better.

In a concert venue, I doubt that the critical sharpness of the edges of the frame will matter very much.  I don't know under that application what is best.  Perhaps the XZ-2 with its better JPG colors would be more pleasant?  The manual focus of the XZ-2 is also very nice to use, and it would be very usable if the AF had problems.  The tiltable screen of the XZ-2 might also be essential for taking pics above other people's heads, for instance.

At high ISO, the LX7 gives smoother (less apparent grain) results, but the XZ-2 gives sharper results, so I think that the underlying sensors are similar, and you should be able to compensate by tuning the in-camera noise reduction up or down.

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Luca