There are clearly many alternatives, but the two machines I've seen operating, (because I've commissioned work from their owners), the first one self focuses, but retains that focal point throughout the operation, so only really any good for flat work - the second also self focuses but continues to refocus throughout the operation, so ideal for cylinders, like a pen. That machine cost £14000.
I hear that the cheap machines out of china for a few tens of quid are pretty useless for all sorts of reasons. The cost of the machine also often does not include the cost of the software apparently.
