Any weed-eater guru's out there?

I have a friend with a small engine repair business. For weed eaters he recommends 2 options. 1,buy high end,such as Stihl,Shindawa,etc.,and keep maintained as required,and they will last for years. 2,buy cheap (under $100),and when they quit in 2-3 years,throw them away,and buy another cheapie. In the end,you will have spent about the same.