I've only participated in one block swap and it was the black and white one on this board. It was great and all of the blocks are well done. I did the Secret Santa swap and that was great too. I am now doing the International Round Robin II and we're just completing the second round and they all look fantastic.
I don't know if I will sign up for any other swaps since I have limited time after work and weekends and there are so many projects that I am working on and want to do on my own.
As for all the people that say they like working with un-washed fabric, I used to be that way until I started using starch. I liked the stiffness of new, not the limp of washed, and it seemed that no matter how much I ironed the wrinkles of washing never quite came out. Using starch is amazing! Wrinkles come right out and I can make the fabric as stiff as I want to and I usually make it stiffer than un-washed. It makes my piecing come out so much better.