I have had two with the modules in place, both installed by previous owners. One was an SXLAO, the other an XL500. The SXLAO was a devil to start, always wanted to pull the rope out of my hand. Once it got going it was Katie bar the door, it cut like crazy. I sold it and 2 years later the new owner had not been able to pull hard enough to start it. I offered to buy it back but he declined, ?. The XL500 I still have, it is my favorite saw at this point. It has been used and abused before I got it and I have done very little to it. It starts very easily and also cuts like mad. My luck with the modules is 50/50.
Would I install one? Well I have two modules waiting and no inclination to install them. They will wait some more I guess. I do not want to have another hard starting SXLAO but the modules require no maintenance.
I have a Big Red and a John Deere CS350 (SXLAO in yellow and black) that both have factory solid state ignition. Both start easily and run very well. I have another XL500 that has an ignition problem for which I have acquired the parts to convert it to factory solid state ignition rather than the module.
Points are pretty reliable and I am not inclined to take a good running saw apart to install a module.