Difference Between BEx Web and Web Intelligence

Hi,

Could someone help me understand why someone would want to choose SAP BW BEx Web over Web Intelligence (apart from license issues)?

Web Inteligence is a very strong tool from a UI point of view and has can do most of the functions that SAP BW BEx Web can. WebI allows users to actually create your own reports.

A couple of drawbacks with WebI

- I can see is that Web Intelligence does not handle SAP BW hiearchies very well (i.e. they are not shown in a hierachical manner).

- WebI holds the data within the report which can mean long run times. BEx Web only brings back data for fields that are shown in the report

I have heard people saying that BEx Web is an OLAP tool and WebI is not. How does this make a difference?

Thanks