Wagyu is a type of cattle (unique breed with a distinct genetic identity). Kobe is a city in japan that used these cattle (ironically as work animals and not for meat, until less than a century ago). All beef sold in US as "kobe" or "wagyu" is descended from one of 10 bulls that were imported into the US about 20 years ago. These 10 bulls were initially bred with Angus cows; some Wagyu cows have since been imported into US for breeding. So the 1st generation was 1/2 Wagyu, 1/2 Angus. Subsequent generations increased the Wagyu percentage. Different breeders have a different genetic base (depends upon which bulls they had access to and how they bred subsequently). Thus there is quite a bit of variation in meat characteristics between different ranches in the US. The best ranches are better than the Japanese original; the worst ranches are worse. So you just have to shop around until you find the right source of meat. For the next couple of decades there will be enough genetic variation between different herds that there is no consistency in US Wagyu meat quality. However 97% of the Wagyu beef in the US qualifies as Prime (the highest USDA rating), vs. about 2% of Angus beef. I too noticed the big variations in quality and was interested enough to investigate; glad I did, now I can eat great beef at 1/5 of the japanese price.