Didn't think I'd have time to post before hitting the road today, but here goes:
It's [u:1vmqgrsz]awesome[/u:1vmqgrsz]. Difference in tone - None. I have a pretty good ear, and I can't tell a difference. The big change is durability. Because they're Stainless Steel, they will never tarnish, and because they're a stronger alloy than the SS strings, they won't wear out - at least not for a long time.
Above all, they're pretty and shiny

That said, it is harder to work with, so I can see why Sheldon might want to keep the current style around.