Craig, what do you mean 'no way to toggle a bit in a single instruction'? XORLW and have it store it back into the register. At least I think that might work.....

Interrupts - you're lucky to have them - the original PIC did not have interrupts! This was an add-on that came later. Yes, and you have to poll the interrupt sources to figure out who called as well as making sure you've saved the code and register page register. Just think yourself lucky you've got a 8 level stack.....Puts the 8051's stack limitation into perspective.

The code and register banking was also an add-on to the original architecture. The PIC18 started to get a little sensible, the PIC24 is a totally different beast.

My first micro was the National Semiconductor INS8050 SC/MP - much the same age as the PIC and not quite as elegant. This had no stack and no subroutine calls - one would XPPC P2 (exchange pointer with program counter). Count your blessings!