Has anyone heard any pros or cons on the SCS stern drive unit?????????

Depends on what you want to use it on.

Check out the Turbine Superboat thread in the Superboat section. Guy installed one, looks awesome, never did get it dialed in correctly.

Apparenly very strong, and pretty heavy, but not as heavy as sixes. I think they are a good concept, but havent heard anyone using them other than that one instance.