1. The Sony and Panasonic "international" models have no Japan warranty.
2. Among the overseas models there are only a small subset of the ones that Sony and Panasonic sell all around the world. And almost never any newer models for several months, sometimes longer, sometimes never.
3. The "international" versions are 30-70% more than the "local" versions. The only difference in them is that the "international" version has the firmware that allows the menu language to be changed -- just like Sony and Panasonic cameras have that are sold outside Japan. Keep in mind that this much higher price is for a camera without a Japan warranty.
4. The "international" versions are usually kits with a lens so if you just want the body you are out of luck.
Earlier this year the first crack in the dam appeared. I was in Tokyo and talking with a worker at Yodobashi about a Sony model. He told me that recently the "international" version includes a Japan warranty. I then asked about Panasonic and he said they had changed recently too. Later I verified that information. Okay, still very expensive, usually not the latest cameras, a subset of what the companies sell, and often part of a kit, but at least you get a Japan warranty. That isn't enough of a change to get me to buy one here though, but it is a small, welcome change.
Now there is another, much bigger crack in the dam I discovered a couple of weeks ago. The Panasonic cameras that have come out this year have the regular, non-crippled firmware that allows you to change the language! The Panasonic GX7II (aka GX85/GX80) and very new G85/G80 both allow it and I verified it at a store by changing the menu language while playing with the cameras. Since they are the regular models the price also is the regular price without the huge markup for an "international" version -- and you aren't forced to buy a kit.
Unfortunately, Sony is still Japanese-only.

Fortunately I now have the realistic choice of choosing Olympus or Panasonic bodies for my m4/3 lenses and flash. Just like everyone all over the world outside Japan has always had.
