It is a bit of hit or miss in some parts.

Valencia-Madrid? Very fast and good, even with a low cost operator.

Valencia-Barcelona? Not as good, but it still beats the plane.

Valencia-Málaga? You mean Valencia-Madrid-Málaga, plane makes much more sense.

Valencia-Badajoz? Again through Madrid.

Madrid-Badajoz? Fuck you.

What I love the most about train is that you can go to the restaurant car and stretch the legs.