PICs are better, cheaper and smaller.
PICs are also more official being programmed in C, not a new language.
PICs are using less power.
PICs are not just pro prototyping.
CONCLUSION: PICs are better than Arduinos
Raspberries are also better.
Arduino's language is basically C/C++. Anyone who knows C can use an Arduino. It was actually a platform we were considering using for the first year programming course in our university where they teach C++. The only reason we didn't use it was because all you can do with an Arduino without any separate hardware is blink an LED and we didn't want to add any complexity.
I never liked PIC. We have to use it for a project for first year. Compared to Arduino, the process to get the code on board is way more complicated. As for less power, I have no idea, but the fact that Arduino is open source shouldn't detriment from it's value. I could be biased because that was my only experience with PIC. I think the university likes Atmel products better, because my experience with microcontroller boards after that have all been Atmel and I really liked it.