It appears that the SC has more circuits that help it with the 'extra' compensation. I had a Lectron back in the late 70s and loved it. The metering rod on the 'new' generation Lectrons is vastly superior to what was available in the 70s. A rod can be ground that is similar to fuel mapping on fuel injection thanks to computer grinding techniques. The Lectrons appears to be 'simpler' than the SC while still doing all or most of the the same functions. + Lectron has been around for 30 years. You are right about "where have they been" though, the drag racers got wind a long time ago about the simplicity of the Lectron and kind of took over the Lectron market, as far as temperature and altitude compensation, check the snowmobile guys, they are running the same Lectron at the winter drags and the summer grass drags.... The SC is the bomb diggety but I don't think the Lectron is a bad choice either Just my .02 worth