My previous post detailed my frustration with my gas trimmer having the line continually jam and snap in the spool. Further research shows I am not alone. So I am now looking at a replacement head, but there are a number of options, so I need some feedback. I have seen one by aero-flex that uses helicopter-like blades, and another named "hassel-free head" that uses 8" pre-cut lines. There are several more similar and all cost around $20-$25. I need something that can withstand an occasional strike to concrete edging and sidewalk without snapping. Any suggestions? Thanks!