I thought long and hard about it. I had a great time last year, really enjoying the talks and especially meeting everyone. It's one of the best conferences I've ever been to.
But when I put on my homo-economicus hat, I can't justify the expense. Since my bootstrapped project is still not my main source of income, the limiting factor for me is really time, not clever ideas of how to do things better, which generally tend to filter out onto the internet anyway.
I'm really envious of everyone going, though, have a great time!