OpenRules provides the non-technical Excel way for a business user to easily modify and manage the rules. Sometimes we found Drools is a little bit overkill for some small and quick projects and we found Roolie is a not bad option as Drools alternative.
As an open source rule engine and product suite, Drools is well suited for the small and middle scale business to manage and integrate the rules to build the rule-driven system which can process the business-critical data and events to produce the automated decision. It is better to use Drools in the well-secured environment (back-end behind the DMZ), not putting it on the customer-facing front or exposing it directly the to public where may bring direct security risk in the enterprise environment. Drools still needs a lot hardening on the security side.
Fusion doesn't support persistence of working memory, which brings some extra high availability risk to our business.
Guvnor still has a lot room to be implemented, it is not so user-friendly for non-technical people, so a lot of business users complain it is hard to master.
Rule execution server doesn't even have JMX implemented, hard to be monitored.
Drools is still lacking support for key Web services standards.
The IT department quickly adopted Drools as it is a very good java-based rule engine, which saves a lot of time to meet the project timeline and balanced our business requirements.
Recently we start considering the OpenRules, which may be more business user-friendly.
