Generally with a pure three phase application there is less concern with return current over a neutral, load balancing is done naturally using 3ph loads. The big bullet point is that the power density is much higher with a 3ph system than with single phase, making it especially useful for dense PDU or cluster type loads. If you have incoming building power that is 3ph, using 3ph everywhere else eliminates the need for having a stepdown transformer(s) between utility and the "end load".

We have several white papers that are relevant to the use of single phase vs. three phase power, which can be found here. If you have further technical questions please call our three phase/Symmetra PX team at 1-800-800-4272.