Now that most vendors offer a diverse variety of ARM Cortex-M chips, why would one pick a Renesas or Freescale product? I understand that there are reasons for somebody to go with a PIC32 as they are familiar with tools etc, there also reasons to use a 16 or 8 bit MCU from TI or Atmel as they might think it's somewhat more suitable for their design, but why would one want to use a Renesas RX or Freescale ColdFire?
1\$\begingroup\$ If the volume is large enough, even moderate factors that make a particular chip (including it's peripherals) more suitable or cost effective for a task can justify dealing with a new software architecture. Also, those other designs aren't necessarily new architectures anyway - many of the coldfire devices are 68000 family descendants. \$\endgroup\$– Chris StrattonSep 26, 2013 at 16:53
\$\begingroup\$ I usually look at peripherals and price. \$\endgroup\$– DoovSep 26, 2013 at 17:56
\$\begingroup\$ Damn, I had a feeling this will get downvoted ;~( \$\endgroup\$– errordeveloperSep 26, 2013 at 18:01
1\$\begingroup\$ @errordeveloper: don't get discouraged by downvotes, especially not one. \$\endgroup\$– Gustavo LitovskySep 26, 2013 at 18:04
1\$\begingroup\$ somewhat related thread: electronics.stackexchange.com/questions/37423/… , although it deals with a wider set of choices \$\endgroup\$– Nick AlexeevSep 26, 2013 at 19:38
I think the best answer to this question, which gets asked a lot, is to look at a good survey. Embedded has a very good survey and it includes many factors.
Look at it and you can see many of the factors motivating people:
UBM Embedded Market Study 2012
Some of the factors you mentioned, and many others are covered and reveal a wide variety of factors play into the selection. Familiarity with the parts dominate, but the strength of the ecosystem is very important.