[GeekyBear]

Google conducts the exact same scans on their own servers, which means the results for a single false positive must be handed over to anyone with a subpoena.

With Apple's system, no data hits their servers until multiple images match known examples of kiddie porn.

If there is a single false positive, Apple won't even know about it.

You can't provide data you never had, so Apple's system is much more private.