My pasta machine (for polymer clay)
I can't offer you a rating of pasta machines because I was lucky enough to own only one, meaning, the one I bought never broke or failed to do it's job so I never had to buy another one.
I can't find it on Amazon, here's just a general search for pasta machine. Mine is Belgian, the brand is 'Artemio'.
Pasta machines are used to condition polymer clay: make it a certain thickness, helps create a continuous blend of two or more colors, gradients, make the surface smooth etc...
If you're serious about making jewellery from clay, this is an essential tool, that will make your life so much easier.
Whatever you do, don't use your clay rolling machine also for pasta making. Or buy a second one. Clay may be non-toxic but remember it's basically softened plastic.
Just remember you can use polymer clay as nail polish remover when you've ran out of one. ;) Seriously. After noticing that you'll never want to have it near your food preparation area.