PIC32 and Stellaris series both lie between the high-end microprocessors and low-end 8/16 bit microcontrollers. Both architectures are designed to be best fitted into microcontroller and deep embedded applications. However, they are powered by the cores of very different vendors competing in architecture market.
PIC32 is the flagship product of Microchip Technology Inc. while Stellaris is now owned by industry leading Texas Instruments (TI). PIC32 is powered by very efficient M4K core from MIPS while Stellaris is powered Cortex-M3 from industry standard ARM architecture. Both the series have their advantages and disadvantages.
Architecture wise both the controllers are very similar with M4K a little more efficient with 1.5+ DMIPS while Cortex-M3 with 1.25 DMIPS performance. PIC32 can pull with ful 1.5 DMIPS performance while Stellaris is a bit lagging.
PIC32 has a great base of 8/16 bit PIC developers. No doubt PIC is the king of 8 bit market. Microchip offers the same MPLAB IDE for all 8, 16 and 32 MCUs. Stellaris, although, does not have such base, but ARM is most widely used 32 MCU. So Stellaris has the advantage of a huge number of “brotherly” MCU vendors like NXP, Atmel and ST etc.
The peripheral sets are also very much the same with emphasis on communication peripherals like CAN, Ethernet, I2C, USART, etc. So one can do pretty much everything he wants to do. Both MCU series have lots of memory around upto 512KB with Stellaris an advantage of using external program memory as well. PIC32 lags in this point that external “program” memory can not be interfaced with it.
Stellaris have a great upward market. With the helm of devices with Cortex-A5/A8/A9 which provide best properties of application processors. This area is somewhat weak for PIC32. With Microchip, you end up with MCUs only and getting upwards means changing vendor, tools and everything. Though working on application processor is really different from that on MCUs, from Microchip one really needs to look around where to go? (Here I tried to answer this question). There are some very popular and successful stories like Ingenic from China or Alchemy series from NetLogic, but they are not great in number. One thing different about MIPS is that they are well penetrated in the market but only in deep embedded applications. It is difficult to find them into general purpose MCU market as one can find ARM. Often MIPS licensees ignore to mention the great power of MIPS behind their products’ “tag” which, I think, is bad marketing effort from MIPS team. But they are there and there is no doubt about that. So the best available option is to move to extremely power efficient and feature enriched media processors from Ingenic.
Anyways for an MCU user PIC32 and Stellaris offer almost the same. Both are solder friendly and hence hobbyist friendly. But they deserve a good presence in professional markets as well.
For 8/16 bit PIC users, PIC32 is a great step forward. For 8051/alike lovers, Stellaris is good, though it’s not a bad idea to taste both of them and decide yourself what suits your requirement and which is more in-lined with your previous experience.