WHAT WE NEED is one of those unbeatable EL REG Comparison charts
The RPi, is a bit of a compromise, not backwards compatible physically, amateurish mechanical design (components piggy-backing, paucity of mounting holes, off-matrix pin layouts). Our company even bought a couple with a view to using them in a school product.
Now comes TI, a classic name in integrated circuits, with their new BeagleBone Black with 2Gbyte of on-board storage pre-loaded with Linux. AND it comes with a USB cable!
Raspberry Pi has an ARM11 core, strange, no other small board competitor does.
Then there are ODROID-U2 and ODROID-X2 from Samsung with a powerful Quad-core Exynos 4412. The U2 is an ultra-compact offering, smaller than the Raspberry Pi. Armed with 2GB of RAM, 100Mbps Ethernet, 2 x USB 2.0 connections,an audio codec with headphone and microphone jacks. For video there is a micro HDMI connection is supplied and for storage, options of micro SD and even eMMC. Android 4.X and Ubuntu 12.10 will be compatible out of the box (it even comes with an enclosure). $20 pricier than the TI.
For our school-targeted projects we are using PicAXE networked with a BeagleBone Black.
Accessory board pricing should be a consideration. IMO RPi add-ons are high priced.
BUT WE NEED one of those El Reg comparison charts to sort the wheat from the chaff.