I dont know that it will build up faster initially, but due to its nature, I am of the belief it can adjust faster than can other types of filters. But that is kind of a misleading statement, let me explain...
Nitrifying bacteria reproduce once every 24 hours. They will not do it any faster, thats just the cold hard biological fact. Therefor, you are going to have a set amount of bacteria reproducing every 24 hours.
However, the number of bacteria can be influenced by the media that they are provided. The more surface area, the more bacteria, obviously. But also, the more food and oxygen they recieve, the better off they are going to be. The best filter that provides this is the Penguins and Emperors with the bio wheels. Properly set up wet dry's come in a close second.
The FBF is far superior to either of those in one category, surface area. This is where it ends up passing the other filters.
The bacteria will only grow to amounts that match the food source, ie ammonia. No more bacteria are going to grow than the amount of ammonia produced will support. So at this point, all the filters are relatively equal.
Now, when you get a sudden increase in ammonia, a fish dies, your kid accidently dumps a can of food in the tank, etc., the FBF has a lot more are available for the increase in bacteria population. In other words, it isnt going to get overcrowded nearly as quickly. So in that way, the FBF can adjust "faster".
Faster is not the correct word to use though. The proper way to describe it would be that FBF's are more adaptable to sudden increases in ammonia levels than other filters.
But to say that they aquire bacteria faster, well thats just not knowing or accepting the simple biological fact of reproduction time. The neatest filter in the world is not going to make those bacteria reproduce any faster than they are physically capable of. Period.
