I am co-owner of a shop, and we have access to a Plek (off-site) for our customers. I've seen it used many times and it's a great machine. For day-to-day setup work it's arguably overkill, and we find it useful when:
1) a guitar is way out of whack - either because someone who didn't know what they were doing messed with it, or when several people tried their own different way to correct a problem. The first thing the machine does is to take a "map" of the fretboard and frets (under string tension, which is important), and compare it to spec. This can save a lot of time and aggravation in identifying the problem(s)
2) a customer wants something that would be difficult to achieve by hand. For example, having all of his frets be consistently lower on one side of the neck
3) a customer wants the assurance that he's getting "the best" setup he can buy
A Plek is used for different reasons in a factory as opposed to a repair shop. In a factory, it is a work- and cost-saving tool, since the company no longer needs a trained person to finish the fret work. Someone puts the frets in, and the machine does the rest - consistently. In a repair shop, the machine is used to bring an older guitar back to spec.
In my view, the machine really shines in a repair shop, and I love seeing customers when an older guitar comes back to them playing like a dream. In a factory, it's simply another production tool.
It should be noted that - unless you want something unusual - a good guitar tech can set your guitar up just as well as the Plek, for a lot less money. The Plek, however, can do this much more quickly, and can do it consistently every time.
Has anyone seen/observed a PLEK in action? More info?
