Assuming that it's the same screen, same camera, same processor, same speaker quality as the iphone 5, then I would consider it.
Why? The aluminum that Apple uses, though it's a metal, just isn't always a great idea for a phone.
It bends, and it deforms pretty easily. Not to mention scuffs that were present from day 0.
With plastic, I do not feel the need for a case. A 5c naked will be thinner than a 5 with a case, and likely more durable.
Then again, I'm a person who doesn't like aluminum for macbooks either, yet like everyone else, I buy them anyway b/c there's nothing else like it so I deal with aluminum.