romulus,
The expression basically means that there is a great distance in terms of quality between the best and the second best prize.
The adverb 'Far and away' could be simplified to 'far away', 'by far', or even 'far'.
-Far away the best prize that life has to offer
-By far the best prize.....
-Far the best prize ......
"Away" is added for emphasis with the meaning 'very' or 'to a great extent '.
examples
Back in the days of the neanderthal.....Away back in the days of the neanderthal.....
Down South in the land of cotton.......Away down South in the land of cotton......
Other expressions......it would be hard to find one as poetic as 'far and away'.
By a wide margin the best prize that life has to offer....
By a mile the best prize.....
Out and out the best prize....
Out and away the best prize....actually this means almost the exact same thing.
Without a doubt the best prize....
The very best prize.....