Like all N scale there's nothing really exclusive about Fleischmann products vs other manufacturers in the same market. Any collector of European N scale will probably be as equally familiar with Fleischmann as the next, but it really depends on what your questions are. It also really depends on the vintage of your focus; modern Fleischmann products are exclusively N scale, being owned by the same company that produces the Roco brand in HO, and in my experience their products aren't any different from any other modern European N scale products (albeit the quality level is very high).
Outside of Europe they are probably known mostly as making steam locomotives but really they offer every type of product as Bachmann or Kato for example - track, train sets, individual rolling stock. The stuff I have is all modern production Swiss electric locos and rolling stock. All of it is very high quality but then again so is what I have from Brawa, Minitrix, Pico, etc.
I have no experience with any of their older catalog though as I only started collecting current production European N scale a few years ago.