Syncro Spark
1: Easier starting if your engine has a magneto.
2: Some have reported a slight RPM gain, I did not.
3: Once timing is set, it usually doesn't vary
4: No moving, vibrating parts to wear.
I converted my G62 from the hard cranking magneto to the Synchro Spark, and it has been a joy to work with ever since.
Vince