I regularly use the smaller brother to this chip (18F6722)
I have found no surprises migrating from 18F452 and 16F677.
The chip is very stable and does exactly what the data sheet says.
Note that there is an additional register to set up for the extra a/d.
The 22 version is a good upgrade to the 20 version adding low power
and enhanced everything and internal oscillator.
I designed inhouse, a "brain" module that houses the chip and xtal on a small
board with dual rows of pins (like a stamp). This allows this module to port to any project and freedom from re-doing the chip layout each project.
Melabs has an adaptor for the 18F8722
http://www.melabs.com/products/adapters/surfadpt.htm