I bought my Klippermate around the Year 1999 or so. It has surely "paid for itself", not merely in the dollar costing, but in the fantastic ability it has given me to fine-tune my racquet's on-court performance: I no longer wait and wait until strings are dead, or use dead strings; I know what strings work best for my frame, thus an improvement, etc.
I really like the Klippermate. It's good for learning on, and it's quite possible to use it forever. Mine cost about $135; I picked it up at the company office in Elgin.
Now, knowing what I do, it's easy to question whether it would have made more sense to pay another $2-300 for a better machine; one with fixed clamps. But all told, I've now got a good feel for how it all fits together, so I'm not sure I'd buy the more expensive machine even now. I know how this one works and how to make it do good things for my racquet.
To Praise, To Bless, To Preach--the Dominican Order