What else do you notice?
Other than the notes and syllables, of which we dilineated upon greatly in our last blog, Tony's HAS phrasing. As opposed to David, whom as you pointed out sings every word and phrase with a similar volume and emphasis, Tony crafts each phrase with a line that has a play, such as "in delay there lies no plenty", but also bends the rhythm and tempo to add even more emphasis to certain words, as well as to draw out the meaning of the phrase.
What are the aspects that make one singer sound professional and accomplished and the other, though talented, less so?
Again, the vastly different phrasing, singing of notes, and syllables make a huge difference, but as the singers fall into diction, to name a few things, Tony's English is more clean and clear. With David's singing, words like "endure" and other simple things like how in the phrase "where are you roaming", how he puts together the words where and are to be "whereare" make it less pleasing to the ear. Another word, "Kiss" is also sounds like "ih" as opposed to Tony's "kiss" which is rounder and more full, instead of chopped off and shallow like David. Finally, a touch different between the two singers is how David scoops into many phrases, in contrast to Tony's clean notes that are more clean in their approach.
It’s easy to say that one sounds better but why is it?
Well, it certainly isn't the recording. Overall, the reason for one sounding more professional (better) is the combination of all these harmonious techniques, such as shaping of vowels, playing, but not too much, with the phrasing, and finally the different emphasis in each syllable, as oppose to David's equal emphasis.
