CALs, KALs, etc.—who likes to participate, and why do you enjoy taking part?

Dear users, dear authors,
Who among you enjoys participating in CALs, KALs, etc.? These are craft projects where an author uploads the patterns—either for free or for a fee—in manageable portions. The idea is to work on the project together, sometimes exchanging ideas with fellow participants and, of course, with support from the author. CAL: crochet along, KAL: knit along, etc.
Did I summarize that correctly? Anyone want to add anything?

Who among you likes these projects (or doesn’t)? Who has already participated, and who would still like to join in? Where did you run into difficulties? What could be improved?
Let me know your thoughts.

Does anyone else want to add anything?

I just downloaded Part 9 of the Annual Mystery CAL from Morgen Design and am really looking forward to crocheting, especially after all those post double crochets in Part 8! I find this CAL exciting because every new part is truly a surprise.
I also enjoyed crocheting the “Blumenstern” shawl CAL, as well as seeing the photos from the other participants.
I’ve also participated in a sock KAL. It was my first pair worked from the toe up and with a new heel style (though I have no trouble with traditional heel styles).
What’s exciting about CALs or KALs is that even though everyone follows the same pattern, the results turn out quite different depending on the color combinations! And it motivates you to stick with it, especially for larger projects.
So I’m always open to new group projects!