Interesting question, kids.
I started with postality to learn a bit more of about it, and ended liking it so i bought the original from Enterbrain for 60 bucks.
Thing is, You HAVE to have the original if you're planning on selling your game.
If your game is crap or you're just toying around with RMXP, then get PK and save your bucks.
About the 4 lines text limitation: even if the original version and PK games are incompatible, if you turn on both and copy a ten line txt dialogue from the PK editor and paste it into the Legal version, it works
![Grin ;D](https://rmrk.net/Smileys/default/grin.gif)
I fixed my special "hability meditor" event with this trick
![Cheesy :D](https://rmrk.net/Smileys/default/cheesy.gif)