Just my personal experience and philosophy: I have purchased two cameras listed as "Grey - International Model" at a savings of approx. 27% each. Most of the time when I look at International pricing I see a savings of about 17% at best. But I would not purchase International if the savings wasn't at least 25%.

And no, I don't worry about the 1 year Mfg. warranty. I always buy from a source that offers a no questions return policy for 30 days. Plus there is a 98% chance a camera will not need warranty eligible repair during the first year, according to the statistics. And if you have one that does, you can always find places to repair any camera.

As I said above, this is just my personal philosophy on camera purchases. I have no quarrel with anyone who would be nervous purchasing Grey. There is no right or wrong in this matter.

Numerous comments have been made about how buying grey market products leave you open to problems if you have a fault with your purchase and that it may well have to be sent back to Japan for repairs etc. This may well have been true in the past but certainly here in the U.K. things have changed.
There are several well known retailers of grey market camera equipment over here, Panamoz, HDEW, Cotswold Cameras etc. I bought a Canon R5 from Panamoz and was able to track its shipment step by step to the U.K. from Hong Kong, as it happens exactly the same when I bought a new iMac from Apple last year.
Apart from the significant saving in money, all these suppliers give a three year warranty, that’s both bodies and lenses using, in my case authorised Canon repair specialists. What’s not to love??

I was, once upon a time, a Canon camera user. I changed to Nikon because every time Canon brought out a new model, you would be looking for a new set of lenses for it. I used Nikon equipment for many years and never needed repairs. But the idea that if I was in a foreign country and bought a Nikon product they would not service it warranty or otherwise is not acceptable. A few years ago I found that the Nikon equipment was just getting too heavy for me and I moved over to Leica. Their products come with an International Warranty and no matter where you bought it they will service it under warranty or if no longer covered will repair it with a reasonable fee. This is how the world should work, if they made it and it is defective or has some user induced problem they should repair it. My 2 cents worth.

Well, I have no personal experience or legal training on this, but I think the issue goes back to having authorized dealers or service centers. To protect the dealership agreements, long ago they did not allow sales by dealers in other regions to compete with each other or undersell each other. I believe such arrangements were long ago found illegal, and in any case, by mail or Internet, people can buy anywhere today and manufacturer warranties are valid anywhere. Of course, a store does not have to take defects for service or refund if they were sold elsewhere.

I think if I get a brand new defective product made by Nikon (gray market or whatever), I have a valid court case for compensation from Nikon, though some states are more consumer-protective than others. Dealer warranties and manufacturer warranties apply independently from each other--dealers can be here today and gone tomorrow, even in the USA.

My Canon camera has the model number of the Pacific market (different name from USA name and number), but it still came with a Canon warranty which I sent to Canon. The dealer warranty was just the 30-day eBay option to return for refund, so the dealer has little or no warranty service in the USA, and may not exist today. I have had no problem with the camera for 12 years.

Why are grey market cameras generally cheaper than cameras intended for the U.S. market? Because in most of the world outside the U.S. cameras are cheaper. The manufacturers know that U.S. customers are willing to pay more, so they charge them more. It's about maximizing profits by controlling the price according to region. Refusing to service grey market cameras is simply the manufacturers' approach to punishing U.S. customers who did not buy a camera intended for the U.S. market with the higher price tag.