It has a strong literary focus. Capclave's motto is "where reading is not extinct," and they own it. If you mainly go to sci-fi conventions for the literary track and tend to find yourself with a lot of free time, or end up going to panels that don't sound terribly great because they're the only writing or literature panels available for that slot, Capclave is the con for you. I've been to much bigger cons with much more robust programming where I had hours of down time because I'd hit a six-hour chunk where all the programming was about shows I didn't watch, or about anime (which I like, but my tastes are hopelessly out of date), or cosplay (REALLY cool but not something I do), or podcasting (Godspeed to all you podcasters, but I'm not one of you). If you're an anime-loving cosplaying podcaster, Capclave won't have much to offer you.
If you're there for the writing and lit, though . . . yowzers. I'm looking over the schedule for this year and weeping audibly at all of the conflicts. Why, oh why, must the "Language in Fantasy Worldbuilding" panel, the "Submitting Your Work to Agents" workshop, and the "Alternate and Secret History" panel with TIM FREAKING POWERS be at the same time?!
It's small. Feature, not bug. For one thing, the small size means that Capclave can keep that literary focus because it isn't trying to cast a wider net and draw in every kind of spec fic fan around. It's focused on lit as surely as Otakon is focused on anime, and that's OK.
The small size isn't just a subcategory of "it has a literary focus," though. Capclave has an intimate feel that I like. I've been to some panels with only about half a dozen people in the room, and the audience participated as much as the panelists. It's much easier to get into a workshop that you want, or to run into people that you've met earlier in the con, or to bump into an author that you like (I fangirled all over poor Will McIntosh last year, but he was very gracious about it). At Capclave, I've had panelists come up to me after panels to talk in-depth about a question I asked earlier. I've never had that happen at a larger con.
The workshops are free. Balticon 50 had some spectacular workshops--but I could have gotten good seats to Hamilton for the price of their premier workshop track. Capclave also has spectacular workshops, and you don't have to pay a dime.
The guests of honor are way better than you would expect for a small con. In case you missed it above, this year's guest of honor is TIM FREAKING POWERS. Past guests of honor have included George R. R. Martin, Lois McMaster Bujold, Kim Stanley Robinson, Gene Wolfe, and even Isaac Asimov (Capclave's been around for awhile).
It's cheap. World Fantasy has a literary focus, too. World Fantasy is two hundred dollars. Because Capclave is still a fan convention instead of a professional one, it's still affordable.
Capclave definitely has a niche audience. If your favorite part of cons is cosplaying, or people-watching the cosplayers, or attending the multimedia track, you're going to be bored silly at Capclave, and that's OK. If you're actively looking for a professional convention so you can network with agents and editors, Capclave is going to have too small and fannish a focus for you (although you might still want to come just for fun). If you're a writer looking for a very writer-focused con that's priced like a fan convention instead of a professional one, though, you'll probably love Capclave as much as I do.
Come join me next weekend!