I spent some time today mapping out the similarities and differences between Value Stream Mapping and EventStorming. It's remarkable how similar they seem, and I think the way I've been doing VSM is very close to an EventStorming approach. I don't think you could go wrong with either one, but there are several key differences that will dictate the right tool for the job in any situation. 

EventStorming, as you'd expect, is about events. It's also centered on the concept of queuing and its effects. That's a very different focus from Value Stream Mapping's emphasis on measurement, quality, and value. Where they converge, is a shared focus on flow.

In cases where an organization is just starting out, I think the best recommendation I'd have is to use whichever term and approach seems to resonate best with key sponsors and leadership. Use what will get results, leverage the path of least resistance, build momentum.

  Value Stream MappingEventStorming
Data YN
Method Qualitative/QuantitativeQualitative
Delays MeasuredAs queue S/M/L
Symbology Simple to complexSimple
Orientation Default Left to RightDefault Right to Left
Roles/Actors YY
Quality YN
Lead time YN
Rework YY
Waste YN
Triggers NY
Activity YY
Issue NY
Question NY
Areas identified HotspotsHotspots, Bounded context, Subdomain
Extensions Tools, Artifacts, Data flowRead model, Aggregate, External system, Policy
Core unit ActivityEvent
Focus Work/Quality/Value flowSoftware event flow, queuing
Sequence Current state, Ideal state, Future stateCurrent state, Issues, Questions
Scope Org to TeamDomain to Application
Levels Ecosystem, Org, Release, Sprint, ProcessBig picture, Process modeling, Software design
Parent Lean Process Modeling, 1920+Domain-Driven Design, 2004+
Software design  NY
Market dynamics NY
Superpower Visualized and improved work flow and performanceVisualized event flow and complexity
Resources iSixSigmaawesome-eventstorming