Someone made these points, but I don't think they disprove that it was a missile.
1. The spiral is way too symmetrically perfect. Look at the vortex shape its just too precise to be a rocket spinning around. A rocket spinning would leave different shaped exhaust all over the place as the thrusters from a rocket have variations.
How is it too symmetrically perfect? Here is a simulation of an out of control rocket:
2. The color of the spiral is nothing what a rocket should be. Also there was no explosion just a fade out.
What color should a rocket be? Not all rockets explode when they malfunction. If the spiral was from burning fuel, it would fade out as it burned up.
3. Not sure on the accuracy of this but I read some article that state the rocket would have launched AGAINST the spin of the rotation of the earth and this would be counter productive and uncommon.
It's true that when you launch a rocket you factor in the spin of the Earth. If it's true that the evidence shows the spiral could only have originated from an object moving against the spin of the Earth, that would probably rule out a human launched device. Does the evidence actually indicate the object was moving in the incorrect direction?
More info
http://blogs.discovermagazine.com/badastronomy/2009/12/12/another-russian-rocket-spiral-lights-up-the-sky/