If you own a Black, 1st Gen controller then yes, a Samsung SmartThings Hub is required for operation. Spruce uses the Zigbee wireless protocol, and uses the SmartThings Hub as a bridge.
1st Gen Spruce is compatible with both Smarthings Hub v1 and v2, which was released in September 2015. More information on SmartThings is available at the SmartThings Homepage.
The interface for 1st Gen Spruce is in the SmartThings App, available for iOS, Android, and Windows Phone. It is not possible to use Spruce via a PC or web browser UNLESS you own a 2nd Gen, wifi Spruce controller.
While 1st Gen Spruce will probably connect to other Zigbee-enabled smart home hubs, 1st Gen Spruce has been optimized for SmartThings, and functionality in home automation hubs will be limited, and is untested.