Stainless steel wheels are bright and shiny and don't require much maintenance as they will stay bright and shiny. They are extremely popular with people who like bright and shiny things.
Chrome finishes on wire wheels are not a brilliant idea, as the chrome will flake off as the wheel flexes, and then they look scabby and horrible, and nothing can be done to fix them.
The silver wheels are painted steel, and require a bit more tlc to keep them looking their best. Even better IMO are the painted black wheels, which will make your Morgan look cooler than a polar bear in Ray-Bans. Not that I'm biased, of course
For a 'proper' classic look, painted wires are definitely the way to go, and for the purist one should go for wheels the same colour as the upholstery and hood - which might be a bit tricky as I think MMC only offer silver or black painted wires.
