Bruce is right--it is a very personal thing. Though none of the chefs I know use Forschners, I am sure many do. They are good knives too. I used them, as well as Wusthoff and F.Dick, when I started in the restaurant business. When the Japanese started coming out with high-end knives on the American market I and most of the other chefs I knew at the time switched. This was because the alloys they used were very superior at that time. The edges held longer. I know the French and Germans have improved their alloys since but to me, their knives are heavier than I like.
Japanese-made knives are thinner than their European counterparts, as a rule. Globals, and some of the other Japanese companies, do not bevel their knives' edges, as the American and Europeans do. This allows for an even thinner blade which is ground down like a razorblade. The Americans and Europeans still bevel to 20-22 degrees; the Japanese 12-15 degrees.
Unbevelled knives must be steeled with a diamond steel and sharpened with a diamond stone. If you are used to steeling European knives you'll have to change your approach by cutting your steel angle in half (approximately) to get closer to the 12 degree angle. Pre-angled sharpening machines (like Chef's Choice et.al.) made for American and European knives will ruin an unbevelled knife. MAC, Global, and other Japanese companies make manual machines for use with their knives.