Another person who experienced mixed responses. My first one, a friendship block exchange (different forum) where we selected color of our choice and made a particular block, sending them to hostess who swapped them out (one from each participant & returned to us in postage-pd envelope), was wonderful. Great hostess, lots of feedback from participants as we worked on our 20 blocks and everyone came through with great blocks. Second: birthday block swap (another forum, 12 participants). I ended up shorted 5 blocks. Pin cushion swap okay but took several nudgings through hostess to get mine. I spy fabrics and other fabrics/fat quarter swaps -- positive. Another birthday block swap (still another forum) -- only 7 others in it, two poop-outs (early-in-the year birthdays who evaporated into thin air, after their birthdays of course. Mine was last in the group (midDec.). All-year Secret Angel Swap (this forum)-- excellent! Lots of nice things received and great getting to know my Angelee and at end, my SQA.
I agree with others, watch how well things are monitored by hostess and how specific the rules are (blocks defined in terms of acceptability, timing, etc.) or if for other things, how defined amounts to be spent are, etc. Myself, I prefer a one-end point swap (as opposed to all-year or ?) and prefer shorter time-frames as unexpected life-events getting in way are less likely to happen. If you go into it with idea that it might not be perfect, you'll be happier.