The new visitors center is very nice, and includes an "Exhibition Hall" where they have models of DC from the time the first capitol building was built all the way through the present, so you can see how the city evolved over the centuries. A statue of King Kamehameha was front and center in the new visitors center, I recognized him right away. I couldn't tell you who any of the other statues from the various states were!
The rotunda is gorgeous - though after seeing way too many OLD European domes, it looked so new!! There is a beautiful frieze at the base of the dome which depicts the history of the U.S. from Christopher Columbus through the Wright Brothers. It took 75 years and three different artists to complete.
Unfortunately, we were not allowed the see the current Senate or House floors - you have to get tickets from your Congressman to attend a session in order to do that. We did get to go down into the crypt though where there is a compass in the floor that marks the point at which DC is divided into its 4 quadrants.
Overall, it was a nice tour and we all agreed, it was nice to be there fewer people - I expect the place will be mobbed once it is open to the public!