Raspberry Pi 3/2/1/0 vs. Beaglebone Black vs. Intel Edison

Model CPU RAM usefulness
Raspberry Pi 0 ARMv6 512 MB LPDDR2 obsolete: high power consumption, weak CPU.
Raspberry Pi 1 ARMv6 512 MB LPDDR2 obsolete: high power consumption, weak CPU.
Raspberry Pi 2 ARMv7 1 GB LPDDR2 obsolete: old CPU compared to Raspberry Pi 3, no onboard wireless.
Raspberry Pi 3 ARMv8 1 GB LPDDR2 excellent quad-core CPU, GPU, onboard Bluetooth/Wifi.

The Raspberry Pi 2 benchmarks and Raspberry Pi 3 benchmarks are very impressive and show far faster performance than the Raspberry Pi 1/0. Using the graphical desktop, the Raspberry Pi 3 is useful for basic desktop use.

Beaglebone Black

Beaglebone Black had been a much better choice than the Raspberry Pi 1 due in part to the PRU DDR3L RAM (faster), and ARMv7 CPU nearly twice as powerful as the Raspberry Pi Zero/1, native Ethernet, onboard SSD (eMMC), better onboard I/O (for local sensors), etc.

Intel Edison

Intel Edison is a better choice for energy-budget conscious tasks than the Raspberry Pi and the Beaglebone Black due to the Edison’s dual-core x86 CPU, fast RAM, and extremely favorable Intel Edison energy efficiency. Depending on your application, the Edison may run 10-20x as long or more on battery than the Raspberry Pi (1, 2 or 3) and Beaglebone Black.

My opinion on the original Raspberry Pi (non +, model B 256MB and 512MB RAM) boards was fairly limited due to the anemic ARMv6 single core CPU of the Raspberry Pi 1.