THE most sonically dissappointing (lp) you own of great music?

Brian Ellis Group- Escondido Sessions. Suffers from home brew DIY production but damn! 

Agree with op on War on Drugs

i have yet to pick up an original but I do have an A&M half speed, "audiophile" series of Jobim's Wave that I may have listed as a letdown, it wasn't exactly cheap either, but that wouldn't be totally fair till I hear the original. 

I have 2
1) don Henley I can't stand still. Record was too bright no bottom end whatsoever.
2) mgmt oracular spectacular seems as sthlugh the music was compressed not good!

Adele - 19. Amazing songs and a great voice. "Mastering" could've been more accurately described as practicing. 

Toscanini conducting Beethoven's 9th Symphony in a live recording from the 1950's. Great performance, dreadful sound quality.