Why do you say that Drools 2.5 is a "different beast"?
Could you please elaborate on that?
There are a huge array of changes since 2.5 - completely different rule format, the internals have been rewritten (more complete RETE implementation, etc), IDE support, and so on. And assuming you see all or most of these as improvements, you could argue that Drools
2.5 isn't as good a rule engine.
That said, if it does the job for you, it's a viable choice -- we still have projects using 2.5, and it's not posing a problem for us.
- Geoffrey
--