I'm biased because I work there, but I recommend the Pertronix kit. There are 3 styles, Ignitor I, II, & III, but for the money, the Ignitor III is the way to go. IT Automatically disables itself so it won't burn up if it is hooked up incorrectly or overheats, and has a built in rev limiter. The warranty is 1 year exchange. You pay for shipping to send your old one in and for the shipping of the replacement one.
The basic ones like the ignitors pretty much all work the same for all the companies, a magnet, or series of magnets mounted on the distributor shaft under the rotor, spin past a module mounted where the points used to go is what fires it.
You can buy either a complete, tested ready to drop in and use distributor, or just the points conversion kit for your dist.