OK, as long as you're not mean to cats...
The original Farley doesn't quite have enough movement to cover the 100 yard score target, without loosening up the screws on the dust shield. Then it does. It can also benefit from Butch's new teflon pads, and a rebuild along the lines Butch has outlined in several posts on BR Central. Or, Farley will retrofit the original rest, but for a significant amount of money.
I have both an original Farley and a Shadetree. I've used the Farley much more -- why I bought the Shadetree top -- but in truth, haven't used Shadetree enough to give a good evaluation. I have a friend who had a Farley top only, and was not satisfied until he *significantly* rebuilt it (he's a machinist).
At this point, I'd go with a Shadetree, but remember, that has more to do with my frustrations with the original Farley than anything else. To show you how long I've had it, I believe I paid $600 new, just as the son was taking over the operation. For all I know, all those issues have been resolved with the later Farley rests.
As far as price -- like most things, they're worth what someone will pay. And most well-off folk didn't get that way by being taken advantage of, unless it's inherited wealth...