I've submitted a few sites to BOTW for clients, but it's really hard to tell whether or not it's worth the money. I've never seen any direct traffic from the directory (but I don't track the traffic of all of those sites). It's impossible to say how much (or even whether) the link improved rankings. All I can say is that Google has always been pretty quick in picking up a listing there, so it seems they crawl it deeply and often.
Do you think it's worth the listing fees to submit a site?