If there was any lingering doubt over Microsoft's ambitions, their latest adCenter announcement makes it clear they're aiming right at AdWords. Note that, at least for now, adCenter's Quality Score doesn't actually effect where ads appear in search results (unlike AdWords scoring, which dictates placement and CPC), it will simply give advertisers a better idea of how competitive their ads and landing pages are for certain keywords.
Our bet is that this is temporary, and it's only a matter of time before adCenter starts using these scores in the same way as AdWords. This could be Microsoft's way of stepping around Google's patents or it might be a way for Microsoft to test introduction of the scores.
These scores could give observant advertisers greater insight to increasing the performance of their campaigns, however it remains to be seen how many advertisers will optimize on the new QS metrics. They certainly seem like useful metrics to increase the overall performance of your campaigns.