I own a BL 4-736...it does not have the differential feed. I bought it new and used it in the beginning for making clothes. I no longer sew clothing, but still find many uses for it. Just this week I made 26 aprons for our church. The men grilling chicken will wear them to protect their clothes. It's a good, basic serger, and I've only had mine serviced once in almost 20 years when I sewed (well, tried to sew) over a pin hidden in some fleece! I have actually perfected threading it by tying on all four threads and carefully pulling them through the loopers and the needles. I've thought about getting a new one several times, but just don't know what more I could do than I do now. I think your purchase might depend on the price.....I probably wouldn't go over $75 or so.