Primavera P6 - Which Software Package?

Hi, I’ve seen threads for P3 and P5 showing differences in packages, but not for P6 - apologies if I’ve missed it.
Can someone therefore tell me the main differences between the packages Oracle provides (bearing in mind I’m new to Primavera and used to Powerproject and MS Project - yes, yes I know)
I work in Construction, should I get Suretrak? Would that be too limiting? so do I need Contractor? PPM? ePPM?

What would you recommend in short please apart from obvious price?

Thanks very much for your help.