Currently got 3 Pylontech US3000C setup with my interver and connected as per the Pylontech installation guide. 

 

 

Are there any advantages to connecting each battery negative and positive to a central busbar, and then onto the inverter? 

I will only use a Busbar when you load is more than what the cables can handle.

You can also double up on the cable from batt to inverter. If you have more than 1 inverter it can also help having a Busbar to connect the bank of batteries to multiple inverters.