I went to the Reina Sofia when it was free - after 6:30 p.m., I believe. Get there a little early as there will be a line. Since I don't speak Spanish, I bought an audio guide, but was really disappointed with it. There weren't many things that had an audio guide translation, so I just wandered around for most of my time there.
Of course, I would never call it a bad experience, because there were several long audio readings of Picasso's Guernica. It talked about the piece, the author, the history, the meanings .. very worth it and incredible.
There's also some interesting experimental art I enjoyed looking at.
Overall, not a museum I would see twice but not one I regret seeing once.
Also, there's a sculpture outside that looks like bacon.More