A few opinions, please...
I've been working with ARM7 and now Cortex for several years (embedded systems, not consumer items).
I may be mistaken/naive but it seems that this ARM/embedded market is dominated (market share) by NXP and ST Micro. Again, not talking about ARMs with MMUs.
Would you go down the Atmel road with low-end ARM/Cortex? Are there facts that bolster the prudence of Atmel in (low end) ARM-land?
Atmel Studio 6 seems focused on Cortex/M3 and that's a positive sign - if it matures and proves to be a viable alternative to IAR and Keil (in the professional tools space).