mbed microcontroller

Have any of you got your hands on these babies http://mbed.org/? I am certainly not going to trow away my beloved Arduinos any time soon, but those mbed mircocontrollers seem really interesting. The features include 60Mhz/32bit ARM Cortex, 512kB flash, 32 MB ram, 3 UARTs, USB, ethernet, real-time clock etc. It has breadboard friendly form factor, although slightly larger than Arduino Nano. It has web-based C++ development environment. I looks to computer as an USB-stick, and uploading a sketch is simply copying the sketch in to it. The price isn’t bad either, Farnell sells them at 54,69 ?, although they have none in the stock yet.

I have not actually checked, but I got the feeling that mbed is very ‘closed source’?
Not at all what I look for in a development-/experiment-/prototyping-platform.

On the other hand, if mbed is open source [software and hardware] then shame on me.

It was a bit hard to find info about licensing issue, but here is something I found:
http://mbed.org/forum/topic/119/. In briefly, the PCB design and documentation will be released under MIT-style open source license. The core libraries will be closed source, although free for commercial and non-commercial use, because they want to avoid forking.

The web based development environment is kind of two edged sword. It is of course very convenient if you can start developing without need to hassle with installing development tools. On the other hand, I will worry what happens to my project I they go belly up or for other reason decide to close the site. I think they should provide also an off-line development tools before it can be used for anything important.