PB's potential lies in being able to script many different features without them being explicit features of PB itself. For example,
body armor is easily scripted using PB but is not a feature. An
inventory system is also possible through scripting, though admittedly it does require a bit more work than with RPGMod. The idea with PB is that we shouldn't put a cap on the possibilities of the Mod, and allow the user to make their own features.
PB also has the "nextlevel=X" command to go to different levels, and it's not very hard to set up a way to have the level end immediately for this change to take place. RPGMod does retain a level's layout when revisited, though, which can be difficult to reproduce in PB.
Cash in a game is nothing more than a variable, and with PB's ability to easily display variables on screen through a numeric HUD, it's also an easy task to maintain. Buying items is as easy as activating them for pickup and taking away from your money variable.
As for which game I would enjoy the most. I am quite partial to either genre, though I think you will have a much easier time making an FPS game in an FPS engine.
The one and only,
Only those who sow the seeds of their desires will reap their benefits later.
However, I have seeds of my own to tend to. I don't have time to be someone else's watering can.