I've had an iPhone 5 for 3 months now and love every thing about it. Being a macbook owner this phone was made for me. However I like the colours of the 5C and like the material more than the aluminum back on the 5 and 5S. Is it worth switching?
I say go for it. We have reached a point where the 5, the 5c and the 5s are all amazing devices fully able to do pretty much anything you can do with an iPhone. The great thing about this generation of devices is that we have a huge variety of choices to fit what people want, need, and can afford, and they will still have an amazing device. If the hot new feature for you was the colors, then I would deff get a 5c.
It has a better battery , so I would say go for it. But if you are pretty much satisfied with the metal build of the 5 and you don't have any issues with the standard battery life you get with the 5, stay put with it till the next flagship iPhone arrives next year.