I participate at PBF from time to time. Its a good place to go if you're looking to get started into backpacking or looking for info on a specific piece of gear. Finding what you need is pretty straight forward since there isn't much off topic buffoonery to sift through. The draw back, is just that. Its not a very personable community like the one here at TLB or over at BPL. I find myself drawn more towards posting at BPL since the SUL stuff and nerdy gear talk is very interesting to me. Though I find myself stopping by here quite often because the members are a bunch of fun and there's always something interesting going on.
There are many people that are members at all three of the sites and provide great information in each but you don't get to know people as well at PBF.

Adam