Personally for me i enjoyed Little mermaid more, it was 1989 and i was only 9 and am going to admitt this, i fell in love with Ariel,. call it homo or whatever. i admitt she was my first cartoon crush. i always wondered what she look like without the Shell Bra. Imagine a 3some with Ariel and Jessica Rabbit.
As for the Lion king 1994. being more advance it got better production and animation. but to fight which is better movie is like oranges and Apples. I think its personal preference.
everyone has their own favourite Disney.
Mine is Aladdin i have not enjoyed another disney as much as Aladdin. Largely because of Robin Williams made it one of the best cartoons.