The Elektron APIs - EMA and ETA are our strategic APIs. New features and functionality will be added to the Elektron APIs.
RFA is our feature complete API - we will continue to support RFA for the foreseeable.
Both can be used to consume Data from Elektron. However, some newer features will only be available via the Elektron APIs.
A few other posts with related information...
What are strong reasons to switch from RFA to EMA
Provider sample project
RFA.NET API vs EMA API
