Warthur
As well as providing the album itself in its original mix and in the updated mix by Steven Wilson and Robert Fripp (a fairly tasteful, light update which doesn't mess too much with perfection), this continues the run of Crimson boxed sets which come stuffed with live sets from the relevant lineup.
This box is hampered somewhat by two factors: Jamie Muir really wasn't in the band that long, disappearing shortly after the studio album was done, and the band didn't do many soundboard tapes during this era (the Guildford Civic Hall gig being a happy exception). That means that most of the live sets here hail from audience cassettes, which are somewhat varied in their quality as you might imagine.
Some of them are pretty good - with the Zoom Club and Hull Technical College tapes at least sounding better than Earthbound, and offering full sets. (It helps a lot that the chaotic music that Crimson presents here suffers less from a lo-fi presentation than, say, the material that the Islands-era lineup were performing.) And the Beat Club tape is a live-in-the-TV-studio affair, so that sounds great.
At the other end of the spectrum, the Glasgow Green's Playhouse and Portsmouth Guildhall tapes are really not good - to the point where even the high quality of the music itself couldn't save them as it did with some of the other audience tapes. Still, overall the good outweighs the bad in this collection, and it's well worth it if you love the Larks' Tongues material, want some really massive improvs featuring that lineup, and have a tolerance for sometimes dodgy sound quality.