Pro Large community
It's widely supported and you'll find a lot of resources on how to get whatever you want to do done on Raspberry Pi. It's as of 2014 still the most famous single-board computer (just check eBay).
Pro Supports the Raspberry Pi Foundation
Pro Multiple I/O options
The B+ model of Raspberry Pi has a plethora of Input/Output methods. There's an Ethernet port, four USB 2.0 ports, an HDMI port, audio/video jack, 40-pin GPIO header, microUSB power port as well as DSI and CSI ports.
Pro Standard rectangle shape which can fit almost anywhere
The components of the board have been arranged in such a way that they can don't stick out of the edges of the board itself. This way, the B+ has a pretty standard rectangle shape which can fit in a lot of containers, most of which are rectangle-shaped.
Pro Comfortable place for the microSD
The B+ has a comfortable click-in spot in which the microSD can be inserted into the side of the unit.
Pro Power efficient
The B+ can power peripherals such as hard drives through the USB ports with up to 1.2A shared across all 4 ports. The Pi itself needs 2A to be able to do this,
Pro Great audio quality
The Raspberry Pi B+ has a pretty good headphone jack which supports some great quality audio.