But do you get a free IDE for it? Looks like for some ARM M0 microcontrollers from Nuvoton the Keil IDE is free:
http://www2.keil.com/nuvotonI guess the Keil IDE for 8051 is not free, and usually it costs like $5000. And the N76E003 is 8051 based, and 0 in stock at Digikey, with a minimum order quantity of 1026 ICs.
The SAMD parts are supported in the Arduino IDE, which is free.
If you want to sell 1000 of it, IDE + parts might costs $5250 for Nuvotron, and $730 for the SAMD.
But the Mini51FDE looks interesting. It is an ARM Cortex-M0, 24 MHz, 4 kB flash, 2 kB RAM, so it is supported by the free version of the Keil IDE, and you can get it for $0.46 for 1000 at direct.nuvoton.com. This would result in a price of $460 for 1000, and the Keil IDE is much better than using any Arduino or Eclipse based IDE. Too bad it doesn't have USB and a bit low on flash memory. But definitely worth to consider for some products, because the processing power would be much higher than e.g. for an ATTiny with an 8 bit core and lower clock rate.
But it all matters only if you sell thousands of it. Otherwise just choose the microcontroller with the best features, or that you already know, because the time you spend to learn the new peripherals, IDE etc., wouldn't make sense (if you need a few days for learning and testing, the salary for it would be higher than what you save on parts cost), unless you do it as a hobby, like I use to do
