The difference between even better and better yet

Hello
Could you please tell me what the difference is between even better and better yet and in what cases should I use them?

Another question: which question correct and why?
Whom are you talking to? or Who are you talking to?

[Tdol]

They have a similar meaning, but only 'even better' can be used in comparisons with 'than'.

I'd say:
Who are you talking to?
To whom are you talking? (formal)

Whom are you talking to? - not wrong, but I don't like the use of 'whom' with the preposition at the end.