Okay so I have used pol, sphere, and runuo and out of them all pol is the easiest and funnest to script on..
Before I come back I have a few questions..:

Firstly I have searched and none of the threads that came up were really what I wanted to know:
What client versions does pol support? Can I use the latest 7.x.x.x clients on pol?

and... well actually I guess that's about it haha.

Latest beta doesnt support the tiles id's up to 0x7FFF nor the SA stuff.

Latest core SVN does, so either grab it and compile or wait for the next beta to use SA stuff with 7.x.x.x clients.

Pol support all clientversions more or less. every new feature is made so it doesnt break the older clients.