This costume was actually the second costume I ever made, and it's been worn many times since then. Last year, the idea for doing the Wizard of Oz theme with my kids all started with this costume.
I used Simplicity #4133 to make the scarecrow costume originally, and when I realized the costume would fit Xavier, and that I still had the pattern, the wheels in my head started to turn about turning my other kids into characters, too.
From what I remember about this pattern, it was a fairly intricate pattern with rafia for the straw, patches on the pants, five different pieces to the costume, etc, but it's the best scarecrow pattern I've seen out there. Just keep in mind that if you're going to make it, give yourself some time.
I also made one change to the pattern. I didn't use their pattern patch because I thought square ones of different fabrics would look better, and when I was done appliqueing them on with the sewing machine, I handstitched large sloppy stitches around each patch with some really thick thread for an added detail.
Don't forget to check out the other costumes from this year: Toto, Dorothy, and the Tin Man!