I had very high hopes for this machine. It has great features, tremendous speed (really, faster than I can handle at full throttle). I bought this machine because the manual talked about being able to sew leather and other heavy materials -- I have some bags I wanted to make with a light leather cap on the bottom. I tried to sew one layer of 1.5 oz leather onto 10 oz canvas, and the machine broke. The hook has been knocked out of synch from the needle, and I now can't sew three stitches without the upper thread being tangled in the bobbin carriage. I am extremely disappointed, and it looks like I am going back to hand stitching for even the lightest leather, and going back to my old reliable 1802 for general use. I will be returning my 4423.