My take on this – which I have tried to express in blogs in the past- is that these wars are all caused by the confusion introduced by how CEP vendors position their offering.

Each vendor appplies its marketing spin on the discussion: http://tibcoblogs.com/cep/2009/08/21/cep-versus-esp-an-essay-or-maybe-a-rant/
Of course, in that view CEP is the superset of everything – including production rules. I reminds me of the assertion made at ORF that BPM is a specialization of CEP…
I have listened to presentations which describe whole systems – from fraud management to originations management – as “CEP instantiations”. That’s an incredibly confusing generalization.

As you know, there are other positions which attempt to make a very clear and dogmatic distinction between event processing, business processes and busines rules. See: http://www.edmblog.com/weblog/2008/11/an-attempt-at-demystifying-cep-bpm-and-brms.html – which is the perspective I support. I find it clear, each technology / approach has a clear objective, and where they meet and how they interact is clear.

Our decision management industry will fare much better once we clarify all these things.

Carlos
http://techondec.wordpress.com
http://architectguy.blogspot.com/

P.S. also note that there is confusion also introduced by talking about SQL-based CEP approaches. They are not SQL-based, they just happen to use a SQL-like syntax for the continuous query capabilities.
http://www.coral8.com/blogs/blog-entry/cep-and-sql-top-five-myths
Another souce of confusion…