I like it, but not as much as I wanted to. That's because I came to the album after seeing them perform together on TV. In that performance they actually did a couple of Zep songs, which I thought were great, and I was subsequently disappointed to find they hadn't included any on the album.
The funny thing was that as I listened to them in this TV performance, the sound of the whole production reminded me LOTS of a Bruce Cockburn album from the early '90s, Nothing but a Burning Light. That album had been produced by T-Bone Burnett. So I wasn't too surprised to see T-Bone there on stage with Plant and Krauss, and then to subsequently learn he produced the album for them.