The first one to my knowledge is DataComplex, which is itself build upon Esper (read announcement here).
The second one seems to be RuleCore, which as far as I recall from previous posts from his lead is build upon the Mule open source ESB and Oracle BerkeleyDB.
DataComplex is pretty open on its capabilities and you can sign up for a free trial. It is also interesting that the focus is "business users", with f.e. google doc integration (ie a line in a google doc sheet (excel like) can be an event in itself), and other interesting things to come out of it.
The pricing is well aligned on any SaaS business. It is a mix of per user and technical capabilities:
- account number (access to management console)
- number of event stream types (not event count)
- unlimited statements and events count (up to the point you overload your instance)
- given memory size for the server instance
RuleCore on the opposite is really vague on its exact solution despite rants like "for situation detection I actually think we are one of the leaders among the CEP vendors". You cannot access any docs, screenshot, architecture diagram, customer reference, or any trial at all. It is thus difficult to figure out who is the target user, but it seems the only supported transport is JMS - so a fairly technical requirement.
Despite low advertised prices at 0.0001 euro/event there is actually a 500 euro/month fixed subscription.
Otherwise you can stick to a 50 times more expensive pricing per event for a 50 euro/month fixed subscription.
The model does not provides any details about actual technical capabilities (shared platform or dedicated instance like DataComplex, etc)
In both cases I think such offerings are worth tracking but without clear business user value and clear abstraction of the entire technical details, the value proposition is seriously impacted.
DataComplex is definitely well ahead RuleCore on building out a value proposition. There are certainly benefits in putting CEP based solution as SaaS offering, but I believe it makes sense when you empower your business users almost immediately. It is not about being affordable as RuleCore seems to argue around, it is about IT agility and business alignment. This is what successful SaaS vendors do: SalesForces, Postini (acquired by Google), etc. SaaS is not just about externalizing hosting.
You might want to read here for some basics
If you are like RuleCore a technology provider more than a SaaS provider, you certainly should consider do what Microsoft just announced: provide new licenses on a per CPU/month or per Subscriber/month basis for the real SaaS business focused vendors themselves.