Metallica released all the songs from the album on Youtube yesterday so I listened to it all throughout the day and picked up the 3 disc set today and it's pretty good. Like you said, definitely a return to form, dropping a lot of the artsy nonsense they were trying with St. Anger and Death Magnetic to a lesser degree, and also having quality production that lowered the quality of what I did like of Death Magnetic. It's nothing amazing, but it's some solid heavy metal from Metallica which is nice to say for once lol
I still feel like Kirk is the weak link of the band, having lost his solo'ing skills years ago and now just devolves into a bunch of bends and wah, but it's not distracting enough here since a lot of the songs are more straightforward heavy metal tunes with a couple thrashier tunes here and there.