What is the difference between TeraData Mechanism and Oracle Mechanism and which is the best one?

Oracle would survive only if your client was looking for purely OLTP based systems. If it's for a DW platform, the obvious choice is an MPP based RDBMS system, of which Teradata is THE leader.I am not sure what kind of "Evaluation" was performed... load times ? complex queries ? User concurrence ? ... was scalability accounted for ?Was there a bench marking done on both the systems ? (This is something normally the sales teams could be asked to do)