I like her because with all those talent shows all over the world, upcoming singers try to sound "good". They try to hit the right notes, but with no artistic interpretation at all.
Adele is great because she writes good lyrics and not only has a good voice and finds the right melody and rhythm for her songs, but also you get the sense that she means what she sings. That she doesn't just get a text and try to make it sound good. But you hear the different "modes" of her voice and her singing, and you know they have a meaning in relation to the specific line/word she's singing.
A truly wonderful artist.
She's one of those musicians that I always appreciate to the point that I listen to their music even without expecting anything, because I know it's not just about performance, but true artistic value and feeling. She doesn't just try to make it sound good, but sings how she feels it. And I'm sure she writes many more songs and sings them in a way which doesn't make hits, and just releases the "good" ones.
I really get the feeling that someone is communicating with me when I listen to her. She's brilliant.