Recently, my team has been working on a SharePoint project. As part of the brief we also have to fixup a few workflows that are behaving badly. We looked at the problem and it was a list that had couple of SharePoint designer based workflows attached for doing item updates and email notifications based on changes happening to the list items. One might think SPD can do it easily but, oh no, the requirement was to do date based checks on a regular basis along with reacting to the updates made to the list items. This needed time based loop and Date based calculations and other computations.
The guys spent ~two days trying to get this going and finally gave up. I think I can do this with blackpoint in couple of hours. Lesson: Choose the right tool for the right job. Just because it is free, dont kill yourself using it. Hope this is useful. Let me know if you had a similar or better experience with tools.