3-4 Systems available, the 3 major ones are
DMC II - longest on the market, lots of different pre-programmed curves available, optical sensor to replace the pickups. Sorrow-free product for long time if you make the installation right (good description comes with the box). Make sure you do not make the cable installation to tight, as the little connectors in the big single connector are prone to brake under use. 15 pre-programmed curves (which you would only need maybe 2-3 of, as all the others are useless on your engine setup....), so gives a little flexibility but without tweeking something except if you use static timing...
Sachse/REDEX kit: small and good system with a fixed curve I think that can be changed only by static timing I think (or reprogramming). I think it comes with a hall-effect sensor, but am not 100% sure. Also easy to install, good kit, slightly cheaper than the DMC II (depending on where you are in the world....)
Ignitech: not really a kit but a box and pickups available, base-plate needs to be machined, rotor can be reused then. curve needs to be programmed. highest flexibility with different inputs (throttle position sensor, Air temperature or some other possible values can be considered for an ignition map) as well as outputs (fuel-pump, exhup, programmable tacho signal etc. etc), which for sure not everyone uses but could be used for maximum advantage. Some basic maps are available and can be adjusted by yourself. Installation is just for advanced users I would say.
so - if you look for an affordable and good, worry-free solution, go for the REDEX/Sachse kit.
If you look for some flexibility and don't mind spending some extra, go for the DMC II
if you look for maximum flexibility at lowest cost and don't worry about the hassle, go for the ignitech.
HTH