MDS vs AS
MDM / MDS is an application for creating and maintaining master view of reference data / master data. This application maintains policies and procedures as well as work flow management. Master data is slowly changing reference data shared across the whole enterprise. In most organisations the classic example of MDM are Customers and Products.
In the data warehousing or BI world all the master data would be used as Dimensions. MDM has central repository for reference data that is highly available across the enterprise. This would allow anyone to build multiple dimensions. The application can be web based. Security model can be configured to allow users to have limited access to any sensitive data like someone's DOB. This is a server based application and therefore it will be available to business around the clock, unlike master product file on someone's PC.Analysis Services cube is great for 3 dimensional reporting. It allows slicing and dicing using pre aggregated values where possible. Analysis Services not good at managing a change as AS engine is not tuned for edits. AS does allow write back, but very difficult to manage or audit. It doesn't have any workflow, notifications or business rules definition, stewardship built into the system.
I would recommend anyone to use MDS to manage the Master Data at all times and push the data out to source system and data warehouse using SSIS.
Thanks
Sutha