I like the zero-moving-parts (other than the entire unit spinning of course) aspect of that. Don't like the "wastes all the stuff in the middle" but similar units also have waste where you push it through and have to keep a bit on the back side for pulling it out at replacement time. The echo one I use .155, I probably cut 8" lengths and throw out 3-4" of each when they've worn down a few inches, not a great percentage of use, though having bought two 500' rolls for $35 each a couple years ago I have plenty to burn...
Hawkins, what percentage of the entire string that you use would you say is left after the line wears out? How long a string do you cut to thread it through, and how much is left after you've worn it enough to replace with another string?