Samsung Galaxy 4S - Walmart vs Verizon?

Can anyone tell me why I would need to buy my phone from Verizon for $100 instead of getting from Walmart for $49 before a $50 gift card (read free)? Obviously, Verizon says their phones are better (hand tested) but aren't the phones exactly the same? Verizon says it will cost $25 per phone to transfer contacts and pictures but that is still cheaper than buying their phone. Are there any downsides to getting phones from Walmart? If there were I would think they would soon stop selling them because of lack of sales once word got around. I don't want to take a chance with coverage issues by going to Consumer Cellular or Straight Talk. Here in Missouri there are a lot of places in state parks in the southern part that coverage is spotty at best which is why I no longer have AT&T. The plans offered at Verizon and Walmart for minutes, text, and data are the same. Its just a matter of where to get the phones that I know I want.
THANKS TO ALL!