"최고예요" or " 최고에요" as far as I know, the word with a consonant + 이에요 -the word without any consonant + 예요 For ex: 학생이에요? 의자예요? However, a Korean friend said to me: 최고에요. I think 최고예요 is more correct. Anyonw, who can make me clear? Tks!