RaspberryPi v2

[Steve_M]

Just launched today. Supposed to be priced the same as the B+

A 900MHz quad-core ARM Cortex-A7 CPU (~6x performance)
1GB LPDDR2 SDRAM (2x memory)
Complete compatibility with Raspberry Pi 1

http://www.raspberrypi.org/raspberry-pi-2-on-sale/

Update:

This version is not yet compatible with the HeaterMeter project as per Bryan's post here.