Even at a glance it's easy to see how different This Gown's finish is from the other silvers; while a foil, it dries to a suede, matte finish that sparkles as it diffuses the light. The other three shine (as opposed to being matte) and are more reflective. This is especially true of the middle two, the Zoya and the Orly, which aren't a smooth, chrome reflection, but they're definitely the smoothest of the bunch. Between those two I didn't see any major differences ("Major Differences..."), but if I had to nitpick I'd say that Dazzle is slightly more reflective while Trixie lies a little smoother, levels itself a little better.
The Bandi is actually a sort of midpoint between the OPI and the others, only the formula is much thinner--it needed at least one full coat more than the others to reach the opacity they showed at 2-3 coats. All four polishes applied like a buttery dream and were easy to control.
Top coat doesn't change the appearance of the "other three" polishes, beyond adding that bit of finish it always does, but when I hit OPI This Gown Needs a Crown with some, I literally exclaimed, "Sha-ZAM!" Because I am exactly that dorky and because it is exactly. that. incredible.
Of course it occurs to me at the precise minute I start writing up these notes that I still have OPI My Signature is "DC" on my VERY NEAR FUTURE shopping list. A sane person might say, "Hmm, but you have four great silver foils right here. You don't actually need that new one, do you?" Happily, sanity and I are nodding acquaintances at best.
BUY ALL THE SILVERS!