I use the smaller RAM 2420 extensively without any issues. Admittedly, I'm not using anything over the ADC's and PWM modules (and all the other pins as Digital I/O) but they all work flawlessly. And I've almost maxed out the Program Codespace and PBP handles it all just perfect.

The big advantage of the 2420 over the 242 (2520 over 252) is on-board handling of MCLR and Internal Oscillator. This means you have 25 usable I/O pins on the 28-pin package...