To be honest, my kids would rather dress up in something unique, and not necessarily a designated costume. Thrift stores are great for this, since I don't have to worry about it being ruined while they're having their fun.
Why would they want to dress up the same way as everyone else when they have a highly creative mommy. Now, if the site offerred the costumes in bit by bit pieces, instead of whole sets, it might be a different issue since they could make it their own. To be honest, it was that way with their halloween costumes this year too!
Don't look at me! I'm just the passenger!