I have the Brother PC420. I bought it from Amazon 4 years ago and have done a lot of sewing on it. Including some upholstery. It has been a fantastic machine. I have put all kinds of thread through it. It is not picky about thread, though it does like to have it's bobbin case cleaned frequently. I've quilted large quilts on it and used all of the decorative stitches for my wall hangings. I also regularly use it to couch down various cords and other objects for my quilted pieces. It's an amazing machine at an amazing price.
Rob