When we started out with Explore Embedded it was all about learning. Learning how things work to the fundamental level and make them useful in context of embedded design has always given us great joy. It could be tutorials, tiny projects, commercial projects or products; understanding of Embedded Design to the core has also been a great motivation for doing what we do.
So there may be numerous boards based on ARM Cortex M3 architecture and possibly a little more cheaper as well; but we believe Explore M3 will help you learn more about the process architecture, the programming and the possibilities more than anything else. So Explore M3 more about learning than anything else and here is the board.
So here is the board in action. The board helps you prototype with Arduino and take your project beyond with bare metal programming, RTOS support and low power modes. We are making numerous text and video tutorials that you can find on our wiki.