Other 32 bit Micro's seem to be more used in Industry, I am a member at sil labs and I would say Except from me everyone else is a engineer, they talk about other micro's but its always 8051 or some other vendor except microchip for the 32 bit parts.
If you look are say energy micro 32 bit parts and compare them with microchip 32 bit parts, they are very different.
Not saying microchip are rubbish in the 32 bit range but they seem more towards non industry end of the spectrum. 8 bit parts are different, pics get mentioned but mainly 8051 because I think most use KEIL compiler and tools, so use the 8051 because its the same tool chain (sort of). But in many ways pics have the edge in 8 bit, they tend to have more and better peripherals.
But they are generally not as configurable.
Also at sil labs the 8051 has far more posts than 32 bit forum, so it looks like they are still used alot. But I dont think PC32 comes close to any of the ARM range like CORTEX M0,M3,M4. Plus code written for freescale is dead easy to port to any other ARM vendor or part, the pic is kind of out on its own in that respect.
These are purely my own little observations and opinion's I except they could well be wrong. I prefer ARM 32 over PIC 32, but I like pic 8 and 16 as much as 8051 but for different reason's.