Gave it a listen last night. The guitar distortion is overbearing and overpowers everything else (vocals, drums, and bass guitar). Its really overbearing and gets rather old/tiresome after the first few songs. I was just begging for a clean channel or acoustic song to get that damn distortion out of my ears. They even put distortion on the vocals and drums as well. Ugg...
I will admit, I am not a Rival Sons afficianado. I have really only listened to their popular songs (P&T, Swingin', Electric Man, etc.), and this album sounds a lot like those with the exception that they threw distortion over everything and cranked up the guitar in the mix.
In my opinion, it doesn't feel like this album was much of a stretch for them. As for if it is a more grown up, mature or complex album for them... I don't really see it. Musically it sounds a lot like their other stuff. Their orchestration is pretty basic and not really pushing themselves. Its not like listening to G'n'R Appetite for Destruction and then listening to Use Your Illusion 1&2. That was a huge growing up album(s) for them. This Rival Sons album sounds just like another album from them. If you like the consistency from one album to the next, then that's great! U2 is a very consistent band (other than Pop) and they have been going on for 40 years, so it's really not a bad way to go about.