If you're considering it, take the plunge!
I ordered a set from Amazon, then several sets from the website. The set from Amazon (Celine Soft 16 Large) came with written instructions which I really liked. There were also tutorials, and clear instructions showing how to saddle stitch. It came out looking really professional and nice. The following sets were smaller. They did not have written instructions, but the tutorials were clear and helpful. Three of the four came out perfectly and I love them! The fourth one was missing a piece, but customer service was prompt and helpful and has sent me the missing piece. They said they would send it, at no charge, or if I wanted to place an order it would be included. I have been extremely pleased with the quality, clarity, and customer service.