> At Volume Pricing 8 Bit PICs are pretty much incomparable to ARMs. A quick check on Digikey shows that for 10000 pieces, the cheapest 8 Bit Micro is a PIC10 - 35Cents/Unit (that's for today only)... The cheapest ARM Cortex M3/M0 or even a ARM7 is $1+.

I don't think that statement reflects the situation today.

Cost differences at the low end have become increasingly narrow, where they are present at all. Using just Digikey pricing at 10k, as above, it's easy to find M0/M0+ parts in the range of $0.40--$0.50/ea at 10k.

> The smallest 8 Bit micros from Atmel or Microchip or any 8051 is around 3x3mm. Most ARM micros are much larger.

These parts are obviously available in a range of package sizes, but the smallest M0+ MCUs are also 3x3mm.