Eventlog is internally ETW starting with Vista (just for information).
For tracing the Eventlog is not helpful. You would float the eventlog with too many entries. With Eventsource the data are not send until you listen to them (xperf, WPR, PerfView) so this doesn't impact performance.
And if you still need Eventlog entries you can also use EventSource to write to the Eventlog.
Microsoft released a NuGet Package of Microsoft EventSource Library a few weeks ago.
Microsoft explained here how to use it:
Announcing the EventSource NuGet Package – Write to the Windows Event Log
When using Eventsource you have the huge benefit of also adding Kernel providers with xperf/WPR like CPU or DISK and you can see how your application impacts the system.