Developing complex BizTalk maps

When developing complex BizTalk maps using BizTalk mapper using simple functoids will make the map more complex. Recently while I was working on complex maps I faced some situations where we need to write complex XSLT scripts to get the output what we wanted. Using simple functoids increased the complexity. While I was using the custom script XSLT functoids I found following article which suggest different situation where we wanted to use custom XSLT script and guideline for implementing complex maps.
http://social.technet.microsoft.com/wiki/contents/articles/10001.biztalk-virtual-mapper-vs-custom-xslt-en-us.aspx
I hope this article will help you in next BizTalk map you are going to implement.