I've used the disappearing 9 patch and also the 5" with the sashing. The second was tons easier. I found the D9P a real pain in the tush. My first gripe is that it seems like you finally get it pieced and then you cut it up and start over again. Then the seams don't nest. (Maybe it was just because the D9P was my first quilt.) The second one was so much easier to get the seams to nest. Everything was just so much easier.
Every time I think D9p, I think "never again" and I just realized why. Once you make the 9 patch and cut it up, you can't fix anything. Of course, I'll never make Jenny Doan's "quartered stripes" again, either. I would make the 5" charm with sashing and corner stones again at least one more time. It was easy and easy to match up the seams and you can always fix a mistake right up to the end.
bkay