We have already seen the Galaxy S4 go up against the iPhone 5 in a previous comparison. Since the Apple iPhone 5c is basically a repackaged version of its predecessor, this test shouldn't be too different. The only differences are that the newer iPhone is $100 cheaper than the Samsung Galaxy S4 on contract and runs the brand new iOS 7.0 update. While the Galaxy S4 will definitely have an advantage in the specs department, neither device will likely let you down when it comes to day to day use.
We may have favoured the iPhone 5 for its design in the past. But with the iPhone 5c and its plastic design, we have to hand the crown over to the Galaxy S4.
You can read the detailed comparison between the Apple iPhone 5c and the Samsung Galaxy S4 on PhoneArena.