OK, I've had a couple of days to listen to all four releases. First, let me say that I do not think anyone will be disappointed in any of these (as long as you like the music!}. Any complaints are only slight nitpicking and do not have anything to do with the overall quality of the work done by Rhino.
For reference, the equipment in my listening room is as follows:
Sony UBP-X800M2 BluRay player/Yamaha Avantage RX-A1080 Receiver/HSU VTF-2 MK3 Sub/Boston Acoustics Lynnwood VR-20 front speakers and VR-10 center speaker (BA's still going strong after 26 years)/a pair of Klipsch RP-500SA II Atmos Speakers on top of the BA's (not ideal but my only option for this room)/ and a pair of rear speakers that were already built into the wall when I bought the house, so not sure of the maker of those.
For the Quadio experience, I set up the Yamaha to only play the two front and two rear speakers but I did leave the subwoofer in with an 80hz cutoff. I have also experimented with adding the other speakers with mixed results so far.
I'll review in the order I first played them:
Paranoid--nice separation with active movement in parts. In some songs it seems Ozzy's vocals are a bit low in the mix but that's not necessarily a horrible thing. The end of War Pigs is a bit different than the stereo version and I am not sure why. I think that sped up ending could have been a cool use of the quad field. It also seems that some of the double and triple overdubbing on some of Iommi's solos are not present on this mix or are more subdued. Bass and drums sound great. A winner.
Billion Dollar Babies--my favorite of the four, but it's always been my favorite Alice record. The mix is great and very active. I was surprised how many of the lead vocals seem to be centered in the rears instead of the front. Only complaint would be the drums seem to be back in the mix a bit too much and have that 70's compression on them that is the bane of a lot of older recordings. They just don't seem as alive as the other instruments. As has been mentioned in this thread by others who had earlier quad/5.1 versions of this album, there are some surprises on this especially on the original side 2 and even a different lyric on one song which I won't give away. The doo-wop backing vocals at the end of "I Love The Dead" still crack me up every time.
Red Octopus--certainly not one of my favorite albums, but this one probably surprised me more than the other three. A really good mix for the most part although there are a couple of songs in the second half of the record where maybe the original mixer got tired and didn't try as hard. The vocals really shine with lots of play between front and rear and the instruments sound great, especially Chaquico and Sears. Grace's vocals are a little harsh at times but that's just Grace.
Nightmares--this one I had never heard except for the hit single. Not a huge fan of the album as a whole but the use of quad is good but seems a bit amateurish at times. I've only listened to this one once so far so maybe it will grow on me.
I can't wait for more people to get these so I can tell how ignorant I am in my reviews.
Of course, our first question is not about your review, rather...how in the hell do you already have your discs? Do tell....