One thing to consider with a serger is what your intended use is. If you are going to use it mainly for doll clothes and small children's clothes, you will want to consider the width of the foot. The foot on an eight thread machine may be too wide. I have an older Evolve eight thread and it is not that good on curves. I finally purchased a four thread Imagine and it does much better on curves and in smaller areas. "Test driving" different models at a dealer's will help you figure out which machine suits your needs the best.