Great tool from a little-known company
I have chosen Datapolis Workbox as a workflow designing tool chiefly for budgetary reasons (it is not as pricey as other well known apps) an I must say it exceeded my expectations. It greatly improves original SPD capabitilies and in the meantime is not as overwhelming and resource-consuming as other solutions. From our point of view its main advantage is the ability to present workflows in a manner that can be understood by ordinary user, not only SP developer or other tech specialist. Definitely should be more known.
Focused on businesspeople, not tech specialists
Flawless integration with SharePoint
Open to external data systems