Battle Process Explorer, Process Hacker, or System Explorer?

No such thing as best Task Manager. All three have unique features\capabilities that the others do not. For example, System Explorer can create system snapshots and you can compare them. The other two don't offer this.

It really is a personal decision.

I have all three installed as I use each one - dependent upon what I need.

This. Because all three are good on their own.
 
I use three of them..

In purpose for Check RAM and CPU usage, I use Process Explorer because I am more comfortable with its interface.

In purpose for Check which Process that consume bandwith, I use Process Hacker (because Process Explorer don't list Network Activity). This tool can Solve your Bandwith Problem.

In purpose for decide Which Service can be set to Disable or Manual, I use System Explorer. The Service Tab of System Explorer is most powerfull since it can Hide Microsoft Services, See Startup Type of each Service (Auto or Demand), See which Service is Started or Stopped.
Moreover, System Explorer has History tab to Record and Display Process activity.
 
Is anyone using any of these apps to see what DLL files are called when executing a program? If so, in that regards is there one that does a better job than the others? I only have experience with Process Explorer as it has been around forever and ever.