This album is a collection of Alfredo Kraus's operatic performances (in studio or live) over a rather long span of time.
For me, Kraus's prime was in the early to mid-1970's, though he was a tenor of exceptionally long performing demise.
I had his early recording of Alfredo with Callas in the 1958 'La Traviata', and his 'Cosi fan Tutte' under Karl Boehm in 1961. The latter has one aria included in this album, as the entire recording was made under EMI.
Included in this collection is a rather late (when Kraus was past his 59th birthday) live performance of Donizetti's 'La Fille du Regiment' in France. Whoever claims that Kraus was not on par with Pavarotti (or Juan Diego Florez) in the role of Tonio has sadly forgotten that Pav never performed Tonio again since his mid-forties, and Florez has not yet reached 40.
If you compare Kraus with JDF, the main difference appears to be the ability to maintain the legato line even when moving rapidly from mid to low registers to the highest notes. For the voice student, I would recommend Kraus's technique to Florez's.
As for the claim of Kraus not owning a 'very' beautiful instrument, again, I'd urge the listener to dig up some of Kraus's earlier performances in the early 1970's. He definitely had a more beautiful voice than Florez! Only that his major legacy recorded by EMI caught him well past his prime.