Maxilock is the best. You can do alright with SureLock. But some of that thread is too stiff for a serger. The problem we have with cheap serger thread is that it will break (the one that is just labeled 100% polyester -- no brand name on the label). Or the lock stitch that's supposed to stay along the edge, will wave from front to back. I was trying to sew-off a serger with Guterman serger thread, and about every 2 feet of thread, it would twist and form a loop that would pop through the tension, and mess the stitch up every time it would do it. Stick with Maxilock if you can.