Today, I get to eat my words about one polish being a dead on dupe for another. In my defense, though, this is first I've compared these two side by side. For comparison, I bring to you OPI's Teenage Dream and Sally Hansen's Strobe Light.
In the bottle, they look to pretty darn close, almost dead on.
On the nail, though, it's another story. SL isn't as close as I originally thought; it's a touch pinker, the glitter isn't as dense, and it doesn't have the ultra fine silver glitter that TD has. Considering that TD isn't available now, SL is good substitute, and I know there are other brands with dupes out there.
Two coats each, no topcoat. TD on index and ring fingers, SL on middle and little fingers.