I bought "Beatles for Sale" from iTunes the other day because it's the only Beatles album I've never owned. It's not one of their best because it has a very high percentage of covers for a Beatles record, and many of the originals are second-string Beatles: Baby's In Black, I Don't Want to Spoil the Party, What You're Doing. Although at this point that's a plus - these are some of the very few Beatles songs that I haven't listened to death to, so they're kinda fresh and fun. And it's the fucking BEATLES, even their second-string is comparable with most composer's first-string stuff.
Also two of the covers are masterpieces:
Mr. Moonlight by R. L. Johnson
Just the way Lennon jumps on the opening line: MIIIISTAAAAAHHHHH Moonliiiiight! makes it all worth it. I like to crank that up. There's also a nifty organ going on.
Words of Love by Buddy Holly
It's hard to beat Buddy Holly, for singing or for instrumentation, never mind composition. The Beatles certainly loved him. But I think this cover is better than the original. This is no easy thing because the original is so great. And the Beatles were sage enough to keep much of what makes the Holly version so good - the chunk-a-lunk rhythm, the blazing guitar melody, the extra percussion touches - sounds like sleigh bells in the Holly version, and the Beatles go with hand-claps.
AND the extra vowel sound, just a tiny bit, on the end of many of the lyrics:
Hold me close and tell me how you feeeeelah.
Tell me love is reeeeeeaaalah.
Let me hear you say the words I want to heeeeaarah
Darling when you're neeeeeaarah.
But what completely enslaves me in the Beatles version is the very end, including the fade-out, which of course you should crank up. And actually Buddy Holly does this a little too, but what allows the Beatles to go for the win is the Beatle harmonies. Holly harmonizes with an overdub of himself on his version. Three Beatles - John, Paul and George - harmonize together and make some really beautiful sounds. And it's on the fade-out that it really makes a difference. In both versions the end of the song is humming basically:
Words of love you whisper soft and true
Darling I love yooouuuah.... mmmmmm-mmm-mmmmmm mmmmmhmm hmmmm hmmmhmmhmm hmmmmummmm...mmmahhhhh
BUT on the Holly version, the fade-out lasts for only 12 seconds and it cuts out almost immediately after Holly opens his mouth to go ahh-AH-ahhhhhhhh.....
The Beatles do something just a wee bit cooler. Almost the same thing BUT
The Beatles make the mmmmhhh sound for 12 seconds, but they're only getting started - and instead of shifting from mmmm to aah to done like Holly does, they overlayer the ahhhs underneath of the mmmhhhsss and from there to an oooohhhh sound.
Words of love you whisper soft and true
Darling I love you mmmmmm-mmm-mmmmmmmm mmmmmhmm hmmmm hmmmhmmhmm hmmmmummmm...mmmahhhhh aaahhhh aaahaaahaaaaaooooohhhhh aaahaaahaaaaaooooohhhhh aaahaaahaaaaaooooohhhhh
What they're doing is giving the song an extra musico-erotica-emotional impact by going from mmmm to aaahhh to ooohh. Altogether the Beatles hum-along fade-out lasts for 23 seconds before it becomes inaudible, which is pretty long considering their version is less than two and a half minutes.
One more tiny difference - Holly says:
Let me hear you say the words I want to hear.
The Beatles say:
Let me hear you say the words I long to hear
"Long" is just a bit more poetic, just a bit more intense, than "want."
These aren't huge differences from the Holly, but as Michaelangelo is alleged to have said, "trifles make perfection, and perfection is no trifle."
Not that I think the Beatles planned to go Holly one better with an extra musico-erotica-emotional oomph, it just happened intuitively.
Buddy Holly's version
Beatles version