I must admit that I only know about Leonard Bernstein throught West Side Story. The BBC did a documentary about 25 years ago showing him remake it with Dame Kiri Ti Kanawa playing the part of Maria and Jose Carreras as Tony ( i hope I spelt their names right!). With some other fantastic operatic voices, and the backing of a full orchestra, the songs took on a whole new life, far removed that of the classic movie (although I think that in itself was an amazingly vibrant picture). The recording was published by Deutsche Gramphon and is well worth a listen.
From that version, my favourite song was 'Tonight', as it goes from being a bright tune (as Maria plans to meet Tony) to a more sinister one as the rival gangs plan 'the rumble'. 'America' is a wonderfully comic song as the migrants discuss the pros and cons of there new lives in America with the misery they have left behind in Puerto Rico'. Finally, 'Officer Krupke' is another witty observation, this time of the treatment of 'juvenile
delinquents'
Sorry Mariana - I have to say that 'One hand, one heart' isn't on my list of favourites - although 'Somewhere' is (Bobby Darin did a lovely version

)