Depends on what you want out of it, and whether they're offering that.
I went to Pike's Peak Writers' Conference many moons ago (my understanding is that they still do the same thing today) and found three days of very interesting workshops covering a large assortment of genres (including screenwriting, etc--much like FM), with great networking opportunities, easy access to agents, editors and professional all of whom were more than gracious with their time and knowledge. Had a wonderful time and it was totally worth not only the few hundred dollars for the conference, but the airfare, hotel, etc, too.
OTOH, I went to a World Fantasy Con a couple of years ago that I thought was a total waste of money, time and effort. The theme was interesting to me and the programming that sounded interesting in the flyer turned out to be laughable. There was a bunch of boozing (even outside of parties), the parties (the few I attended) were claustraphobic and impossible to have a discussion in and the networking connections pretty much sucked. I did get to meet a few online friends and we ended up exploring the host town & restaurants more than the con, which was the only saving grace of the entire thing. Upon reflection, I realized that what I wanted wasn't what the con was geared for, so of course I was unhappy. The challenge with any world con (Fantasy or SF) is that they always have a different flavor because totally different groups put them on each year, so it's hard to tell what you're going to get. I'd just be really careful about them in the future.
My advice to think seriously about what it is you're going to that conference for, and be honest, and do what you can to see if this con is a good match for your needs. Do the research (talk to people in committee, past attendees, look at programming, etc) and make the decision. There's still some trial and error and no guarantees, just like anything else connected to the business of writing.