Had better (=it would be good to) es usado para dar un consejo fuerte o urgente.
Had better + bare infinitive -> futuro inmediato
You had better apologise to Sonya.
Would rather (=would prefer to) expresa preferencia. Cuando el sujeto de would rather es también el sujeto del siguiente verbo, usamos las siguientes construcciones:
would rather + present bare infinitive -> present/future
I'd rather help you with that later.
I went to the club but I'd rather have stayed at home.
would rather + bare infinitive + than (+ bare infinitive)
Since it's such a beautiful day, I'd rather play football than (play)
squash today.
Cuando el sujeto de would rather es diferente del sujeto del siguiente verbo, usamos las siguientes construcciones:
would rather + past tense -> present/future
I'd rather John told you about the plan because it was his idea.
would rather + past perfect -> past
I'd rather we had left home a bit earlier, then we wouldn't have
been caught in the rush hour.
