ken, I think you should stick with the '887. You already have lots of experience with it and really it can suit your needs just fine.

If you want to jump up to the 18F, you may find yourself feeling like WOW, how do I do this. From what I have found, the 18F's just left me feeling like I had just stepped into a new world with regards to setting up and configuring it just to get it to run. You are doing basic stuff, ie no USB or 4 way PWM with encoder feedback. So the 887 can do that just fine.

BTW, I don't remember how fast you are running the PIC. Whats your osc speed?