I'm definitely in agreement - we will soon have a lot more of substance to judge the performance of Dem's, instead of merely relying on their words.

We should also be watching out for the great talkers who don't walk the walk.  Being in the minority gave Dem's the ability to pretend to be everybody's friend if they wanted to (eg. "I'm voting against this tax giveaway to corporations, but don't worry Mr. Lobbyist, it's for appearances only and my vote won't stop the bill from being passed...").  

In the majority, they'll be forced to commit to one side or another and make enemies of some people.  And that's how we'll find out whose agenda they actually support.