which would be the best raw processor for the XE-1?

Well, the effect is not overstated. It's there. Whether it affects an image is another question as you point out. It's good to know, though, that if one prints large one might run into problems. I do print large. If images are being viewed on the web, pretty much any RAW processor will do.

I think my main concern is that the RAW files can be developed without running into the zipper effect (or moire), so one should expect decent RAW processing software not to be plagued by it.