According to Motorola, the Moto G is "the most successful, highest-selling smartphone in Motorola's history." On first glance, you might think that can't be right, but by far Motorola's best selling device was the OG Razr, which was not a smartphone. The OG Motorola DROID was also quite popular, but it was Verizon only and because of that, it was U.S. only.
The Moto G not only has the amazing price point going for it, but it has also been released in Brazil, Latin America, U.S. Canada, Europe, and India. And, the Moto G was already a best-seller in India before the official release by Motorola. Apparently, a smartphone that offers more than you'd expect for under $200 is a winning formula.
source: Motorola MWC Press Dinner