So I've now listend to the 2014 Remaster of III - the one Led Zep album I know the least and which I have never heard beginning to end as an LP I believe. It's a good remaster by John Davis (there is some debate whether it is identical with the iTunes remaster 2011/12 also by John Davis), not quite as loud and brash as what he did on the 2007 Mothership double CD. I compared a couple of tracks both to the 1990 Remasters by Jimmy Page and the 2007 Mothership John Davis remaster and I find the 2014 offering the most organic sounding, the 1990 stuff was a little too clinical in places, Plant's voice sitting above the music, it's now engulfed by it. The 2007 Mothership stuff was fun to hear for its sheer brashness (sounded like Jimmy page had doubletracked everything anew), but it bordered on being just too loud.
This is now a confident, but not histrionic remaster and the guy who benefits most from it is John Paul Jones. Since his bass playing style is often unobstrusive (compared to Page's many overdubs, Bonham's overloud drums and Plant's banshee wail) and not a constant pulse (lots of space, few repetitions for the listener to latch onto), his bass hasn't been de-relegated to full effect on all tracks (you hear him extremely well on Tangerine, not so well on Since I've Been Loving You, bass frequencies are there, but little focus and attack, perhaps played with the EB-1?), but he is overall much more prominent. HiFi buffs might even call the bass tracks "overcooked" in places, but, hell, this is a bass forum, we don't "overcook" ever!
As for the album: It sure is varied, bravely varied, they did not just carbon-copy Led Zep II. Lot's of Americana influence. I didn't even know all the songs.
Only heard two tracks from the "Companion Disc" so far, an alternative mix of "Immigrant Song" where Plant gets all psychedelic towards the end (and Page's tremolo effect guitar much louder) and an instrumental version of "Friends", sound quality of both is excellent. Oh, and Zeppologists will be rapturous that even the "Tangerine"-version on the regular CD now offers a false start of about 6 seconds and a pause of another 8 seconds until the song actually starts as we know it.