madavid0,
I can answer your question about the $500 SmarTractor. You, or anyone else certainly do not NEED this item. One can do a a reasonably good job correctly aligning a cartridge using one of the many available tools for the job. It is a tool, and like any tool, there are those who can employ the simplest and most primitive tool and still do a great job, while others will need a tool that makes the job easier and better assures success. The SmarTractor is in the latter category. Good tools, like this are expensive not only because of their tight tolerance in manufacture, but because a lot of thought went into the design. The designer of the SmarTractor has designed something that addresses virtually all of the factors involved in both easy and accurate alignment, e.g., the different size of turntable spindles, difficultly in finding the exact center of the arm spindle (necessary for one-point alignment), and difficulty in seeing the cantilever and precise placement of the stylus tip (built in magnifier located at the precise point for proper focus). The designer even offers its own unique alignment (dubbed UNI-DIN). It can do ultra-precise measurements of spindle to pivot distance by employing a vernier scale (it can accurately measure to 1/20 of a millimeter). All of this allows for very accurate alignment. Is that kind of accuracy audible, or otherwise necessary? I don't know, but, it couldn't hurt.
More than the accuracy of alignment, to me, the strongest attribute is how easy it is to do the alignment with this tool. Between taking it out of the box and finishing my alignment (change to UNI DIN) took about 15 minutes, and that includes reading the instructions. My not-so-great eyesight was not really an issue with this tool. I bet it would be a very helpful tool for a shop that has to do many alignments where time is money.