I did one online and I didn't really like the end result but it was fun.
I am now doing another one that just started two weeks ago and I am not sure I will like the end result, but, again, it is fun.
I like how you are given only bits and pieces to work on at a time because they are very easy to finish and I really have a sense of accomplishment each week.
The one I am doing now is a Christmas Quilt / wallhanging here:
http://erikhomemade.typepad.com/
I also liked the ones I did because I only used scraps. There was no monetary outlay for fabrics or anything. So, even though it isn't my favorite, it's ok because I didn't spend any money on it and I enjoyed the process.