Well, I love this trimmer and is apx 6 years old or so and still doining well. Therefore I can compare to the OEM spools and string and self wind of loose roll string and this that just came.My concern was Spool Quality and String Quality. The spools appear as same spec, but are a different mold, marks, -- but if as thick and hard plastic is all I care about. "Looks" that way, so OK. Also the string looks OK too. I have not used it yet but appears as will do OK.So unless I get some notable performance issues later when use it directly, 250 ft of concrete curb lining and etc., I'll leave it there as a good buy at this price point for quality in appearance.If I get a great bargain buy on loose string I now have plenty of spools to load, but, that's allot of work too and if can get them pre-wound, that's my preference. It depends on price and QUALITY of spool and string.