If you tried Edemame pasta, shirtaki noodles, would you say that this one is similar to any of those? Better or worse?

Much better. I've tried all of those. Shirtaki noodles I tried were horrible, the edemame was OK, but these are the best substitute for actual pasta I have tried. made shrimp scampi and I cannot tell that these are not semolina pasta.

If this is 100% from soy beans, am I correct in inferring that it has a good load of magnesium in it? I see it has the potassium you would expect.

I asked the manufacturer this same question - about the vitamins and minerals contained in soy but not listed on this packaging which is supposedly 100% soy. Here is their answer: "These are actually not standard nutrients listed on nutrition labels. The FDA only requires Calcium and Iron to be listed and does not require the ones you mentioned unless the food has been fortified with these nutrients. Our pasta still contains these nutrients naturally from the soybeans used but they are not listed. Please let me know if there is anything else I can help you with :)"

Does it do well in cold dishes?

It works well for me. If you follow the directions on the box, after cooking the time listed, you run cold water over the noodles to stop the cooking process. The pasta is cold at this point and ready for cold pasta salad. It works really well, but I add olive oil or the dressing if it is oil based right away because the noodles tend to stick together if you leave it set very long. If I am using it for a hot dish, I add the sauce to the spaghetti and warm them together in the microwave. Hope this is helpful!

Does this come from china or the usa?

The box I got says: Produced for and distributed by: The Only Bean LLC Grand Rapids, MI 49503 www.theonlybean.com 2018 The Only Bean ® Product of China Certified Organic by CERES