There are a lot of reviews here of people frustrated with the Singer 4423. I was going to purchase this machine back in November, as I needed a machine to handle automotive upholstery and other heavy fabrics. I hesitated on buying because of less then stellar reviews. An Amazon lightening deal changed my mind, as the price was under $100. I received my item well packaged and expediently (thanks Amazon). The directions that come with it are not great, but get the basics covered. I utilized the internet for more detailed instruction, and well as for video guidance. After using the sewing machine for several hours, I too became frustrated. So much so, that I initiated a return. It seems I could not get the thread tension correct, and I would end up with tons of bobbin jams. Nobody wants their bobbin in a jam. After sleeping on it (not literally), I researched more on the internet. I found a few tips that not only helped, my project turned out great and I was able to use the 4423 effectively. My Tips: 1. Use the felt bobbin spacer if the bobbin is racking in the bobbin case. 2. Important. Use only the plastic - not metal - bobbins. 3. Make sure you thread correctly. Thread tension is critical and is managed at loops #3, #4, and #5. When threading, be sure to give a slight tug to ensure the thread has seated into the blind tensioner. Also don't forget to run the thread behind the guide #6. 4. This might seem obvious, but be sure to drop the presser foot. It's easy to forget especially when setting up thicker fabrics/upholstery. If you forget, you'll know soon enough, by having a mess under the fabric on the bobbin side. 5. Practice with the foot control. It launches from 0 to 60 in a split second. I'd like to find a way of better control here, as fine control is challenging. 6. Use the correct needle size. Mine shipped with a 90/14 which is good for many things, but I recommend a 100 for thicker stuff, like chihuahuas and small pets. Just kidding about that small pet crack. I gave this machine 5 stars solely because for the money (<$100), it was a no-brainer. I'd give it 4 stars if priced in the usual $125- $150 range. It's not perfect, as the foot control is too sensitive (like my wife). But it is a well made piece of equipment that CAN handle heavy fabrics. It went through 6 layers of vinyl upholstery as well as plastic piping, without struggle. I did find that best results were obtained when the needle is started manually in the thicker, multi-layered fabrics. Stitch patterns seemed to work okay, but I only did some messing around with them, just to see if they worked. I really only used the straight, and zig-zag with frequency. One other thing, the machine is light, which is good and bad. Good, as it's easy to transport, but bad as it will move when pushing heavy stock through it. Use a rubber mat, or better yet an appropriate table.