I've been to a few presentations on DQS and to be honest it looks like a version 1.0 product. It seems to be a question of shifting your data to the service which given the size of the data would be impractical. The last two SQL Bits sessions on DQS looked interesting but didn't give me a light-bulb moment.

I haven't had the chance to look at Master Data Services yet but it is on my radar.