So it's two metal cards through a rubber band right?

Yeah sorta, there are groves so the rubber band fits perfectly in it and it will never fall over. It is a great wallet I've been using it for almost a year now and have no complaints.

Has anyone had an issue with finish on the metal plates scratching?

After 6 years and 3 months of continuous use, the rubber band is about to break at one short side. The black coating on the steel plates is partially worn only on the high band holders and some edge areas of the plates, but generally, the coating has not scratched off any of the flat areas on the outside of the plates. I generally keep the wallet by itself in a front pocket, keys clipped to a belt hoop, not in my wallet pocket. I will likely buy another of the exact same wallet. Best wallet I ever had! after swearing off the George Costanza wallet style.

How hard is it to pull cards out?

Very easy you can pull them out at once, and fan them out while still in the wallet and pick the one you need before easily storing them back in the wallet.

Is the black paint on the stainless steel components non toxic?

The Radix One Black Steel uses a hardened electroplating process instead of paint, which means that the black coating will not chip off in flakes that can be toxic. Thank you for your inquiry.