I'll focus on the actual experience of visiting the dam, and not on whether I agree with the dam or not.
That being said, it is cool, but I don't think that the $25 tour is really that much better than the $11 tour. It's not like you are going all through the dam or anything, just two more stops - looking down some steep stairs and looking out a ventilation shaft. Cool, but not $25 cool.
Parking and traffic are nuts. There are some bored and dazed looking contractor cops and a few federal law enforcement types, all decked out in swat gear, but more interested in posing for pics with pretty ladies. Your tax dollars at work.
Bunch of obnoxious tourists. Some fool actually jumped up on the wall along the top of the dam to take a picture, but one of the contractor cops yelled at him to get down. I really had to do all I could to suppress my urge to grab his feet and topple him over the side (i'm not a big people fan). Somehow I managed.