Every now & then... Mostly in the past to see if my server admin slipped up in the middle of the night and the servers went down...

(I've got that covered separately now)
Its not bad to be listed there but I personally think it (BB) is losing stature due to the absurd waiting time.. You can pay $$ to get listed quicker, but that is crap, IMO.. I spend hours and hours a day administrating my forums, and I have a full time job as well.. It DOES NOT take that long to verify that a forum qualifies for "Big Board" (500k+ post) status, yet there is an large backlog (supposedly) over there now days.. And if you want to get listed right away, you have to pay.... I guess advertising isn't paying there.
Eventually (maybe sooner than later) someone is going to dupe their system of monitoring sites and open a new and improved "Big Boards" site that actually contains every site that meets the qualifications.. When was the last time they interviewed Gaia or anyone else?
They are cutting their own throat by not keeping up with what they are supposed to be, IMO... The more forums they add, the more that link to them, and the more their directory grows = more traffic = more "clicks" on the ads & recognition, etc.. etc.. Heck, if anyone could have had a "Big-Boards" forum, they would have been in a good place for that.. (side thought)
I enjoy checking in there every now and then to see where I place with other admins / forums that I have been "competing" with (not directly - just for fun) for years now, but very little, if any of my traffic comes from there... My traffic comes from Google, Yahoo and other related sites, blogs and so on..
If you don't get listed in the BB directory... Don't sweat it unless it is a metric of standing to you... And, again, if you have the minimum and the money, sign up... If you don't... Your community will still be what you and your members make it..
David