I kinda hate it. Workflows can only be triggered from an “Input Channel” and cannot be scheduled (so we used to have to do stupid things like write a dummy file to a watched directory to kick off a workflow.)
Developing the workflows is a confusing mess of XML mapping, and troubleshooting is damn near impossible for end-users, so monitoring and cleaning up after the workflows fell to IT.
I’ve been much happier since we just started accessing the BOs directly. If you want something similar (and free with your SQL license) that is way more flexible, you can use SSIS.
I completely agree with Pedro - it’s marketed to non-programmers, but even seasoned programmers will have a steep learning curve because it uses such a unique and unusual model.