can't cover it all!!!
Huge difference internally, Externally they do the same thing.
805x family is more a complex instruction set computer (hundreds of instructions) where the PIC is more reduced instruction set and has about 30 to 90 instructions depending on the PIC.
Both have many derivatives and lots of public domain designs and code.
The actual peripherals incorporated in the MCU's really determine which chip has an advantage, which *will* change with the application.
I've used many devices including 805x and PIC, I personally like PIC's as they are fast enough and usually have a timers and 10bit A/D even on the cheap low end devices.