person who invests in an OS engine does so because they want an engine that will give good service for a long time.
Not since they quite selling the SF engines. OS is not known for longevity. They are known for ease of use, and quick break in. The quick break in is part of the reason for the ease of use, and part of the reason for their short life.
For longevity try a Enya, Fox, or the older SuperTigre's (not sure about the Chinese versions).
For bfreak in just be sure it is very rich, a 4 cycle run is not mandatory but helpfull to prevent overheating. Also read your manufactures instructions as not all engines are the same.