PalmOS
When you get a PalmOS device, the system is barebones ala Linux. If you want all the software, you'll have to get it yourself. Even the GUI is simplistic and if you want customizability, you need launchers like Zlauncher or MegaLauncher. However, PalmOS is more 'moddable' compared to WinMob so if you enjoy tinkering with your device, POS is definately for you.

Software wise, they're equivalent but due to design differences, PalmOS devices are less resource hungry. A 400Mhz POS PDA is equivalent to a 600Mhz PPC in the market and 64mb memory is HUGE compred to a 128mb PPC.

And POS devices are cheaper in general.

PPC
PPC's come in many different flavors (unlike Palm's devices) and you'll have more variaty. The software suit is more powerful out of the box so if you don't wish to spend on software, get a PPC. PPC devices are powerful now and many sport VGA screens, dual wireless (Only Palm's TX and the now-in-PDA-heaven TH55/E1 have it), CF slots, etc. If you like gizmo's with the whizbang factor, a PPC is for you.

Stability wise, PPCs and POS devices are quite similar now. But due to the way PPC's handle memory and the 'registry' system of WinMob, you can end up running out of memory and your device will slow down over time (nothing like a good ol' hard reset to clear things up ). It's not a big concern though, so don't fret out.

Ah yes, due to WinMob's resemblence to Windows, new users will adept much easier compared to PalmOS. And with 4 choices of text input (compared to Palm's 2), it's way easier to learn data entry with PPCs.

So...which is better? I like PalmOS more because of its simplicity and moddability but that's my personal preference. Both are the same, just pick one that suits your 'taste'. I hope that helped.

For 2mp camera,i dont think u can get one.
For the rest,i think its possible.