I am not a fan of the Due. It's too big, too complex, too expensive. I want something much simpler, much smaller, and cheaper, but with a bit more oomph than the Uno, or even a Sanguino. I want something I can integrate into future products of my own. A huge chip with 144 pins that costs $8 in any reasonable quantity doesn't fit that description. And that second chip and USB port have to go. (By integrate into my own products, I mean stick the chip onto a board of my own design, not plug the whole thing in, but if it were small enough and cheap enough, then I could do the plug and play thing.)
I was looking through the offerings from Atmel to see if there were any good alternatives, and I really liked the XMEGA chips with their small size, built-in 32mhz resonator and DACs, but since there's not much support for them, and the future appears to be in ARM, I guess those wouldn't be a good choice.
The SAM3S however seems like a viable option. It comes in a 64 pin package, seems to have comparable specs to the 3X8E, yet is less than half the price. So my question is, is the SAM3S basically compatible with the 3X8E, and will the IDE compile for it just fine with the obvious issue of a few ports having gone missing? Or are there major differences in port assignments that would necessitate a new boards file to tell the IDE how to compile for it?
And are there any other Atmel offerings which might be compatible? Would a SAM4S for example, which also comes in a 64 pin package, work with some tweaks? Or are the different arm processor types wholly incompatible with one another?