I paid about $120.00 Aus for my pertronics, plus another $60 for a new new coil as they don't work properly on an electronic coil...At the time they were about $50 in the US online. I can't say there was much of a difference in performance, but no need to change points.
I agree with Quagmire et al. Especially if your low on cash Change the leads first with a new distributor cap, points and rotor button any new leads will work well enough for at least about 3000 kms, the Magnecor leads don't need to be replaced so they work out relatively cheap over time but you can save up for them by purchasing standard ones first.
Also before changing anything there is a little wire running between the moving advance plate and the distributor body. It is an earth lead and needs to be in good condition and not broken as it earths the points. test is to put a small screw driver under it and tug gently. Be prepared for it to break, you can make a replacement if need be using microphone wire from electronics shops. Its highly flexible, small and silicone sheathed. Be careful with the screws they like going south into the guts of the thing...
I actually own a Sun Distributer Tester if anyone in Aus wants to test their distributer I'm happy to fire it up.