I used Simplicity 3594 for this costume (I chronicled my progress on my blog). I made several changes to the pattern - all fabric related.
Here's a review that I wrote up of this pattern:
Pattern Description: Halloween costume with 4 choices of styles: monkey, frog (prince), butterfly, and lion. Each costume has a bodysuit, 'shoes', and headpiece. I chose view A, the monkey.
Pattern Sizing: 1/2-4. I made the 1/2 size which fits my (almost) 6 month old well.
Did it look like the photo/drawing on the pattern envelope once you were done sewing with it? Aside from the fabric modifications, yes!
Were the instructions easy to follow? Yes!
What did you particularly like or dislike about the pattern?
Likes: Ever since I was a kid, I've loved monkeys. Since this is one of the few years that I can put my son into a costume that I select, I thought I had better take advantage and make him a monkey! Overall, I loved the style and the hat and vest make this costume even more adorable (not to mention the giant ears!).
Dislikes: The 'shoes" for this costume are enormous and if my son was a walking age, I have no doubt they would be dangerous for him to wear since he would trip over them. You can see how large they are in this photo
They also look more like pirate or Robin Hood boots than monkey feet. My other complaint about this pattern is the fabric suggestions - they are a bit on the chintzy looking side (the hat and the vest are supposed to be made of felt) - if I had wanted a costume that looked inexpensive, I would have purchased one off the rack. There are also a lot of pattern pieces to this costume - it's not a dislike, but it was just surprising.
Fabric Used: The pattern suggested synthetic fur for the body, fleece for the tummy and ears and craft felt for the vest and hat. Since I was unable to find darker brown fur (a light yellow monkey or shaggy brown was as close that I could find) I opted to use a Chocolate Velveteen for the body. It just didn't seem right to use fleece for the rest of the costume so I decided on a light brown suede for the tummy and ears. I used a home decor fabric for the vest and hat.
Pattern Alterations or any design changes you made: Because I selected fabrics other than what the pattern recommended I made several design changes:
Would you sew it again? Since it's a costume, no.
Would you recommend it to others? I would recommend it to others!