Well, I'm not sure how to quantify "taste and sparkle," but if "sparkle" means carbonation, it appears that Straight Dope tested this HERE and found it lacking. Their method was simple:
- open three bottles of champagne
- recork one, leave one open to the air, and hang a silver chain in the last (they didn't have a spoon small enough to fit)
- in the morning put a condom over the top and shake to see how much the condom inflates
The recorked bottle overflowed the condom, the open bottle inflated it, but the silver chain bottle would not inflate it, regardless of how much they shook the bottle.
The Wine Lover's Page tested this HERE as well and found that both an open bottle and one with a silver spoon in the mouth maintained their carbonation overnight (makes one wonder about Straight Dope's test).
You already found the Stanford writeup (which was quite narrative and inconclusive), and @warren linked to the Mythbusters "busted" rating.
Then, just to complicate things, we have THIS writeup in which some folks took pictures of champagne that had been left open and been kept with a spoon and then digitally examined the poured glasses for bubble count and size... and they conclude that the spoon method did preserve more bubbles!
That's about all I can find on the "myth."
In terms of how to store it, it seems that the recommended method is an air-tight special stopper for carbonated wines, like are mentioned HERE and HERE. Don't know what "experts" to turn to regarding champagne storage, as there's not really scientific literature on this... but they at least do make such stoppers specifically for champagne, so I'm assuming people really do use them.