MetalSlude,
Natty may have a different view on this, but here's mine:
I would have to say that a product that sheets water is indeed better for paint surface than one that beads. Right off the bat, one can see that it will help prevent hard water spots, which also contain contaminants. Now, I would say this is somewhat helpful for those people who don't maintain there vehciles on a regular basis. For most people that come to forums like this, it's not a big concern.
I would suspect that products like Meguiar's Gold Class (and other Meguiar's waxes) are actually formulated NOT to bead water, but to sheet it. I've talked to the good people at Meguiar's, and they assure me that there is protection their after the beading is gone. I'll take them at the word.
In the end, I don't care if a product beads, or sheets, as long as I can tell that it's still protecting, and looks GOOD! The nice part about having a product that beads is..................... it's easy to tell if it's still protecting! Plus, it looks really cool!
Keep in mind, this is just my "un-scientific opinion.