Well the Biff has been released for 2 1/2 months now and it's still being downloaded at a healthy rate given that is is a CFS3 WW1 aircraft. - 2412 downloads as at 14 June 2006.
That's quite an interesting mix. Sim-Outhouse has the largest CFS community and also hosts the Over Flanders Fields forums and not surprisingly the largest number of downloads of the Biff. Interestingly though the Sim-Outhouse total comprises less than half the total downloaded. Most of the Avsim downloads occurred in the first day of release when it was listed on the front page new additions to the library.
It will be interesting to see how the FS2004 version fairs in comparison.