Yeah, i am a big fan of spiritual beggars, and their best work has to be "ad astra"...
At first, i was not too sure about it, since i hear Ammot was on it, and thought those riffs are a bit simple compared to what he does normally... but once you get the vibe, you just know it's not about his guitar playing only..
It's a combination of 70's stoner rock with heavy guitar work, monster riffs, a freakin nice hammond organ!, the voice on ad astra is very raw, just good, thick bass with some really organic drums... please check it out if you are into "stoner rock" or black sabbath, 70's rock... the mix on it is amazing as well!!
"On fire" was good as well, but a bit of a step back... it all just got a bit cleaner, less raw and aggressive... "demons" was a complete stepback, in my opinion.. way too calm and clean, and even less agressive then on fire and ad astra. they replaced their old singer on that album, and i can't say i am too happy about that at all... still, a damn good album though, but "ad astra" defenitely dwells in my top 10 favorite albums somewhere!