Sarah is okay, but everything about her, from the style of her singing to the content of her songs, just sounds so generic. That’s not to say that I haven’t liked several of her songs. Same deal with Chantal Kreviazuk and Heather Nova, both of whose voices I like better than Sarah’s.
Tori, on the other hand, is unique. Her voice just screams raw emotion and it can be quite powerful. Sarah sounds like a trained professional who’s faking it (same reason I hate The Three Tenors and other crap like that).
If Tori Amos understood what comprised good vocalising, and stayed in key for more than a bar … no, sorry, Sarah McLachlan would still be the better singer by a mile. Amos’ career is one of musical history’s finest examples of sustained incompetence, made even worse by the fact that unlike the Avril Lavignes of this world, Amos has potential.
(Not that I like McLachlan’s songs, but that isn’t the issue being judged here.)