I've seen it, I prefere it as my forum choice. But, it's bloated IMO. It is unnessasery for a forum to be bigger than 5meg.
I looked at my smf folder, and it was 6meg something. Thats with an extra theme or two.
*Edit*
After removing my extra theme, and the un needed files it was 2.89 meg. Leaving enough space for an average sized website if you have an account with 50meg of space.