I used my XL-3500i for quite a few years with no tension issues. When I adjusted tension and got good settings I would log it so the next time I used that fabric, and thread combination again I would know the setting for my machine. You do have to adjust if you go from cotton to polyester thread. You also have to adjust when doing quilting with the walking foot as well. If there are loops on the bottom it means your bobbin tension is too tight or the top tension is too loose. Once you learn how to adjust tension properly you will have less problems. I think this is the hardest thing for beginners to learn. When I got my XL-3500i I really focused on learning tension. Because I am spoiled now with automatic tension, when I do have to use mine I always for get how because I hardly use my mechanical anymore since I got my SQ-9050 computerized from walmart is now my small machine. My XL-3500i will be my daughters first machine in a few years when she is older. It really is a good little machine once you get the hang of it. I would recommend the PC-420 if you are looking to upgrade. There are also a few midrange in brothers simplicity line that are getting good reviews. I would go to your brother and check them out.