My best friend has a bubble watch from JAR, one of the very few limited numbered pieces produced in the 90s. It was a gift from her parents.
Joel Arthur Rosenthal (JAR) is without doubt one of the most innovative jewelers of modern times. That said, I do think the demand for his (undoubtedly) beautiful jewelry has been driven by the ultra secretive/expensive cachet, the "sooo exclusive that he chooses who to sell to" perception (he supposedly rejected Gwyneth until Madonna provided a personal introduction), the long waiting list, etc.
Having seen several of his pieces, I must say JAR's pave work is second to none, truly the best in the industry. That's how he first became famous.
Also Rosenthal was one of the first modern jewelers to be truly innovative in his approach - he is famous for mixing metals, mixing semi-precious & precious stones (e.g. burnished silver with diamonds), etc. He is respected for never following trends, but defining his own style (which has been copied by many jewelers over the years.)
What a lot of people don't know is while Rosenthal is the creative force behind JAR, it's his business and personal partner Pierre Jeannet who is the business genius behind the company. Over the years, it's Jeannet who has been calling the shots, including deciding which clients to choose. There were rumours some years back that Rosenthal had fallen ill and had started to teach and train young jewelers to ensure the company's future.
There's been quite a number of fake JAR jewelry that's made its way in the marketplace particularly in New York, I've seen a few of those replicas (made with real gems but using JAR designs) and it's scary how good those replicas are.
I do think today there are a few jewelers that produce jewels of almost the same level of quality and beauty as JAR.