No iPhone 4 is different from another antenna wise (excluding that one iPhone that caught on fire). The iPhone 4's that do experience signal attenuation are in weak signal areas. I can back this up with a recent test I've done. Stand pretty darn close to an AT&T tower and try the death grip (no drop in bars). There aren't any faulty iPhone devices out there. Like Steve Jobs said, "Every smartphone has a weak-spot."