OLAP vs ODBMS,tradeoff,etc

I am trying to decide whether with an OLAP server interfacing with the RDBMS can meet performances with ODBMS with say Time Object Manager of Object Store.

I would be interested looking at sales information for say of a particular product in selected geography in a period of time. or in a particular geography a set of products over a period of time. and then drill down the geography, or perhaps the product category.

I am currently not looking interfacing this data to any off the shelf business decision tool, but looking at the design point of view of what does the job more effectively, and evaluate the feasibility of such a development with an ODBMS as opposed to looking at say SQL-Server with OLAP, or Oracle with its OLAP Server.

Any reflections, thoughts,etc.

Cheers
Atishs

-- 
Eats code, sleeps with OO, dreams of Patterns -- and still mutually exclusive