I have been playing guitar (all styles) since 25 years and I have been a huge fan of D'Andrea Ultra Plecs since 15 years, when I first discovered them. I had the old transparent ones, the ones you can't buy anymore, because they were sadly discontinued (maybe there are some 2nd hand on ebay). Ultra plecs are definitely my favourite picks, so I was very happy to see that D'Andrea has started producing them again!
The new Ultra Plecs are as good as the vintage ones: Very hard, super smooth surface and round dark tone. If you play jazz you should definitely try them immediately.