Live Bootleg CDs - Are they legitimate? Good quality?


Went to my first record show yesterday ... Wow! Big event! I no longer do vinyl, but they had lots of CDs from which to choose. There was this guy there who had only live bootlegged CDs. I'd never seen these types of recordings before.
He explained how many are very good audio quality. Some recorded directly from the soundboard, some from famous bootleggers, such as Mike Millard.
And they are rated for their audio quality as well, rating printed right on the CD.

Anyway, I got talked into purchasing a couple of double discs which interested me:

Carlos Santana & Mahavishnu John McLaughlin, "House Of The Lord", Seattle Center Arena, 9/7/1973, Rated "A-", Black Oak Records

And Return To Forever, "Santa Monica '77", Civic Auditorium, Row D, 4/8/1977, by Mike Millard, "The Lost And Found Mike The MICrophone Tapes Volume 41"

Any opinions on these two recordings, or recordings like this in general?

Are they really legitimate/lawful?

rockadanny

@zx10 

Your mention of KMET brings back great memories. My junior and senior years in HS ('73, '74), they were my favorite radio station. 

I’ve bought a few over the years.  The CDs tend to sound better than the vinyl I’ve had but the quality is always lacking to some degree.  Prefer getting copies of shows I’ve attended more for the memory than critical listening. 

Note that after 50 years, copyrights revert to public domain, which is why you see so many CD's these days of live shows from that era, mostly soundboards or radio broadcasts, on Amazon and many other retailers. If the broadcast sound was good, so will the sound of the CD's - I've got a number of them. 

Studio session bootlegs are usually of very high quality a favourite of mine is the Rolling Stones' Black Album top quality with sessions from Toshiba studios, Japan. Another favourite is Mick Taylor's Listen to this Ronnie a superb live performance. Steely Dan were not known for captivating live performances but check out Metal Leg. Another live performance that really captures the moment.