In this case, "Image" is a sort of man made illusion, or perhaps a delusion? History and reality may tell a different story.

The fact is, the Japanese have been producing world class "travel bikes" since the 1970's. These models have also OUT SOLD BMW ... and ALL Euro brands combined ... by 20 to one ... as a conservative estimate, at least here in North America.

Maybe your buddy never heard of the Honda Gold Wing, ST1100, ST1300,
Yamaha Venture (now discontinued), FJR1300 to name just a few?

Kawasaki and Suzuki also made BIG travel bikes years ago (Voyager, Calvalcade). Kawi currently still does well with their Concours 1400, which compares to the big six BMW at nearly half it's price. Suzuki has the successful V-Strom, an excellent travel bike that I've crossed continents on ... 90K miles.

The Honda Gold Wing is a hugely popular bike in North America, probably not so much in EU, can't confirm that.

Another obvious answer as to why Japanese over Euro is the fact that BMW have made several serious mis-steps over the years, putting off or losing thousands of customers as a result. They also cultivated a reputation for arrogance that is not an illusion. But that was "Then".

In the last decade BMW have made great strides and done very well. During the same period, the Japanese have not done enough to compete, remained static (stagnate? ) while BMW drive forward pushing tech limits, improving customer service and remaining competitive price wise too.

So ... there is my short answer.

Can't pick one bike, have owned 50+ since about 1962, plus experience from testing bikes for a magazine for 20 years. (add 50 more)

Growing up in California, BMW wasn't much of a presence until the 1980's. But, if truth be told, my first two bikes were BOTH "European". First was a 1960 Triumph Tiger Cub (200cc single). I pushed that bike more than I rode it and it never ran right. (mostly due to lack of mechanical acumen)

Next bike was a late 50's Vespa 150. Great scooter that took me everywhere. But it was not perfect. Next came a Honda 50 Super Cub. An epiphany!

Not every Japanese bike was so good but suffice to say my introduction to Japanese bikes left a lasting impression ... but took a while to sink in just HOW GOOD the Honda really was. (I was only 16)

Continued with Euro bikes, racing Triumph and Bultaco as a teen, Motocross & Desert racing. They ALL broke down. Soon after, me and buddies got the crazy idea to go to Mexico on surf trips on our bikes.
Several Honda dual sport bikes followed. NONE broke down. Slowly I began to get the clear picture on Japanese bikes.

Lots of bikes since including BMW, KTM, Guzzi, BSA, Husqvarna, Triumph and ALL the big four ... and at least 50 test bikes including HD, Buell and on and on.

Currently own a Suzuki DR650 and a 1050 Triumph Tiger.
But, really, I'm a Japanese bike guy. They stand up to hard use, even torture and almost NEVER break down. Important with a travel bike.

PS: Chris, Have you ever toured a Japanese bike manufacturer? I was lucky enough to get a tour of Yamaha, round '93. Also got a tour of Triumph in 2003 and BMW, Spandau, Berlin, 1993.

Nothing comes close to Yamaha. If you can manage it, do it.