BIP Vs OTBI What is the practicality of moving BIP reports to OTBI?

Summary:

I am recommending that my client investigates the possibility of using OTBI in preference to BIP for their reports (including whether this is just for new reports or actually migrating existing reports too). 

Has anyone got any views or practical experience of using OTBI for reporting instead of BIP? 

Content (please ensure you mask any confidential information):

Examples of areas of views or practical experience might include:

• How many essential underlying table columns are still not yet accessible to you in an OTBI subject area? (For example “Just a few and it’s not a problem”, “so many that it’s not worth trying”, or “most and we don’t even think about it”.)