SquareTrade estimates that the iPhone 4's malfunction rate over a 12-month span was just 2.1%, meaning that slightly more than two phones out of every 100 will die during a year.
Motorola's Android smartphones, including Verizon's Droid and Droid X, are projected to fail at an estimated rate of 2.3%, while 3.7% of HTC's Android devices -- ranging from Evo to the Droid Incredible -- will give up the ghost in a 12-month stretch.
SquareTrade pegged the older iPhone 3GS' failure rate at 2.3%, the same as Motorola's handsets.
"The iPhone is still the most reliable smartphone around," said Vince Tseng, SquareTrade's director of marketing.
To come to that conclusion, SquareTrade analyzed four months of iPhone 4 warranty claims, eights months of Motorola and HTC data, then graphed a 12-month failure rate for all manufacturers based on the real-world curve for all smartphones.