Drools.NET vs Windows Workflow Foundation (WF)

Question

I am currently in the process of searching for a rules engine that works in .NET. Our logic is pretty simple, +, -, *, /, and, or, basic order of operations stuff. However we

Answer 1

the fact that biztalk is not going to be replaced easily by wwf is true. The objectives are very different between them, drools compares to biztalk and not with wwf, reasons, both use the same alogorithm (rete)!!

Now, using drools is something else, biztalk also functions as an ESB, can drools do that?