I always enjoy this mashup:
Now, most teen pop stars have a very generic voice: pretty; on-pitch; but on the whole generic and forgettable. I'd probably cite Taylor Swift as the best current example. Now she gets points for writing her own songs (catchy) and playing an instrument, two points in her favor, but as far as her voice goes... nice but nothing special. Taylor Swift also seems to fit the teen star mold perception-wise. Innocent, dainty, good-girl public image.
Miley really seems to have broken away from that mold as a lot of former Disney stars do, but without going overboard (Lindsay Lohan). At this point it's safe to say Miley's become infamous for her pot-smoking, and seems to march to the beat of her own drum... a bit of an edge. All well and good. For me the thing that sets her apart is her voice. It has a raspy, throaty quality that lends itself well to country/folk/rock songs much more than pop fare. It's a voice with character. One that I can easily pick out on the radio. Actually, the pot smoking probably helps feed this quality. A good example of this is her cover of Bob Dylan's "You're Gonna Make Me Lonesome When You Go".
Now she hasn't written any of her big hits (she's credited on a lot her her studio albums, but usually in a group of names. One wonders how much she contributes, but I digress), but her performances are perfectly cromulent. Her voice actually reminds me a bit of Stevie Nicks. Probably no coincidence her most recent tour was the 'Gypsy Heart Tour'.
I guess I'd just rather hear more of this style from her than the regular pop fare. There's plenty of that on the radio anyway.