SAP Information Steward is a very usefull data profiling tool, its main features I like are:
1. Very usefull during data migration project
2. Very useful before implementing Data quality and data governance strategies.
3. Well integrated with SAP BODS (Data Quality Management and Integration Tool)
4. Business user friendly, any non technical person can also use it for basic process.
1. It doesnot allow any transformation in its rule, though we have a work arround like creating views or using SAP BODS but thats an add on steps.
2. I cannot re-use existing rules in another project, I have to rename them to use it again.
3. Cost estimation should have some help regarding market trends most clients have no clue and its almost in my experience is never used.
This is mainly a profiling tool dont expect too much from it, once you have insight on the pain points I would recomend to use SAP BODS to implement improvements. You can always re run SAP IS task to check current status of data quality.
Mostly during data migration project to profile for data quality before merger. Recently I have also used it for making Data Governance strategies.