Well, the thing about FBSD is that it's users are pretty much all hobbyists, so the length of a manual is a good thing. If Debian had documentation of equal or greater length I can only see that as a strength, not a weakness.
If you count folks like Yahoo as hobbyists.Last time I looked, the FreeBSD community was heavier on academics and IT professionals than hobbyists. For that matter, if you look at the latest Netcraft survey of most reliable hosting sites (http://news.netcraft.com/archives/2009/04/01/most_reliable_hosting_company_sites_in_march_2009.html) - you'll see an awful lot of FreeBSD as well.
Unless you've used a Mac recently - most of it's userland code comes from BSD.I haven't used BSD for about 30 years, now, and a good reference book, that is comprehensive, is a good incentive to have another go with it.
Miles Fidelmannote: I should mention that I run Debian on my servers - I'd be hard-pressed to find a more convenient packaging system. But I have a lot of respect for the BSD world.
-- In theory, there is no difference between theory and practice. In practice, there is. .... Yogi Berra