When I said I didn't think Ronstadt had anything over Jewel, I should have qualified that. Ronstadt is great, no doubt, but there are at least 3 issues here. Talent, versatility, and lifetime accomplishments. I believe Jewel is in the Ronstadt league on the first two aspects, but clearly not the third. I should also concede that Jewel may or may not ever establish that breadth of versatility, but I believe she has the ability based on what I've heard already. I could be wrong (who knows what Jewel's interests turn out to be over a lifetime), but that's my take.
I have always appreciated Ronstadt's technical prowess and her versatility, but I can't remember her music ever moving me as some of Jewel's performances frequently have done. Hats off to all the truly greats, including Ronstadt, but meanwhile, I think Jewel also is great. If I'm wrong, I'm not far off. Also if I'm wrong, so what, her voice still amazes me and I enjoy it more than some of the "greats."
Finally, Eva Cassidy's voice is truly beautiful and remarkably moving.