Why is it that people come out with things like this, saying how much more powerful it is then the Arduino (which computationally it is), then limit the whole affair by making it the same pinout as the Arduino?
The number of pins on an UNO (and previous models!) are limited because the chip itself doesn't have that many more. Even the Arduino team provided most of the outputs on the Mega versions, which to be honest is where I see most of these "Arduino replacements" competing.
Why not, to keep shield compatibility, have the pins where the Arduino shields normally are, then run a second set of pins on the outside of those. That way the board is only marginally bigger then the Arduino, keeps the compatibility with existing shields, yet allows access to the additional IOs. Maybe it hasn't been done as there may not be enough space on the board. If that is the case then okay, but why not put a header at the bottom to break out the rest of the pins, even if it means making the board longer?
As already mentioned, if you are planning to say it is compatible/replacement then it should also use the Arduino's multi-platform language and environment. After all both are open source are they not?
I have been looking at the mBed system. It isn't trying to be a Arduino wannabe, maintains much of the power and outputs of the ARM and is multi-platform (if only because it is all online). The problem I have with the mBed is that it is online only, I guess because they are using ARMs commercial compiler and this is an easy way to only have to buy one copy! :lol:
Sorry to rant a bit there

I love the Arduino for its ease of use, both hardware and software working together and not having to jump around different programs plus the great documentation which has actually allowed me to have a greater understanding of C (more then I have ever had from reading books about it :-)). I used to do PICs but the Arduino has killed that off because I got tired of programming a chip then having to remove it from the programmer, then put it into my test board etc etc. I do really want to get one of these ARM based versions but none have what I have come to love about the Arduino and I don't want to have to learn a variant of C as I am just getting my head around C itself
