There a lot of boards that outperform BBB 10-20-30x times. But both RPi and BBB are more than enough to run an autopilot code.
One of the great advantages of RPi over BBB is 1080p camera module with hardware H264 encoder as well as bigger community.
4 karma · joined January 12, 2015
With Navio+RPi you get a lot of stuff compared to hardware like APMMini: network connectivity (LTE, long-range WiFi), affordable 1080p camera module with H.264 encoder for FPV, a lot of processing power for advanced flight algorithms (as an example - a lot of new features of APM such as EKF are NOT available on old APM platforms) and the overall hackability, which you don't get with any microcontroller based autopilot.