Today I listened to the Frankfurt 1980 bootleg again and I really got carried away by its power. If it just had better sound quality, it definitely would be my favourite then.
IMO it's Freddie's best vocal performance ever, even ahead of Newcastle 1979. He hits all the high notes without straining his voice and feels very comfortable with his singing. The bluesy audience singalong in Now I'm Here is absolutely awesome! He sings Death On Two Legs exactly like the album version, with the original high melody, same with Killer Queen, LMEY and NIH. And it's not only which notes he reaches, it's the way he does – clear and clean, almost effortless, with some wonderful "ornaments". He never did it that good before and after.
The audience go crazy at each song's opening chord, Mustapha and WWRY (fast) are almost taken over by them. This concert definitely would be worth a professionally mixed release.
I agree mostly. It is an unbelievable gig, great crowd enthusiasm, the band is on fire, and Freddie is in great shape. As you say, the crowd is sometimes too loud :D. Anyways, speaking vocally, I would still say Newcastle takes it. Freddie's voice sounds cleaner there, and he reaches like 3 high C's (the note on BoRhap), with more power than ever. Plus, his voice never breaks on Newcastle, the second night. So I think Newcastle is my favorite (the second night), even though the quality isn't great, just OK. Frankfurt rocks though.
Other shows I like are Live At The Rainbow, Hammersmith 75 & 79, and Edinburg 76.