I guess it depends? Problem with the Silver Model was that the stainless Steel isn't coated so it would scratch. But nice thing about the Silver model is you can use Cape Cod to get rid of the scratches.
Problem with the Space Gray model is that it has PVD coating so it looks nice, but once you end up scratching it, you will leave a permanent damage and you can't get rid of it. You can but you'd have to wipe off the PVD coating. I have the Space Gray Model and personally it has held up better than I expected. YMMV depending on usage.