CND Vinylux in Midnight Swim, Decadence, Dark Dahlia, and Weekly Top Coat, $10 each; cnd.com for salons.The Claim: They're not gels, and they're not traditional polishes. Confused? Consider Vinylux the sweet spot between the two. A double layer of color and a clear topcoat hold tight to nails for seven days without chipping and can be easily removed in seconds with cotton and acetone. What's behind the staying power? "The color blends contain particles that bind to the keratin proteins in nails, while cross-linked polymers in the topcoat cause it to strengthen when exposed to natural light to prevent chipping, explains David Valia, CND research and development nails director. Expert Opinion: Consider manicurist Dawn Sterling a superfan. "These formulas are easy to apply, and they stick to nails longer than typical polish," she says. "On me the finish lasted about five days, which is impressive since I'm constantly using my hands." Our Take: We give it two painted thumbs up. A week of chip-free nails had our testers marveling—one reached the 10-day mark and exclaimed, "I'm a lifer!" The best part? No acetone finger baths required.