There seems to be this perception that the PIC has superior ESD protection on its pins - but i have yet to see third party documented evidence of this. Regardless, you always want to avoid exposing the cpu to ESD events as prevention is better than cure. It is always good practice not to have your port pins exposed to the outside world, at least without adequate protection. Good practice would suggest you have some form of buffer.

There was some discussion of this on AVRFreaks last year where the same assertion was made. From what I recall, no hard evidence was presented, just anecdotal and flimsy at that.

Microchip have survived on a great marketing strategy rather than technical leadership. They described the PIC as 'RISC' which was catchy for the day, but the cpu is far from being RISC, but people still describe the PIC as a RISC processor. The reality was that is is a very simple cpu and it was quite fast for the day. Microchip also made their tools free which no-one else did and gave the large corporations special pricing.

For those who have used both the 8051 and the PIC, I'm sure you'll agree the peripherals in the PIC are clunky and programming a PIC in assembler is an exercise in self-flagellation. Interrupts were a clunky bolt-on. I'm referring to the 12,14,16 series PICs here, I haven't used the later 18 and 24 series.