There isn't so much difference between both materials to warrant the purchase of a new wok. While the different parameters can be measured, any noticeable difference will probably stem from production quality or seasoning quality. They are just too similar in specific heat per cubic centimeter (how much you can heat the pan) to expect an improvement. Iron has somewhat better thermal conductivity (how quickly it gives off heat to the food), which is more important in a wok than in a generic sauce pan, but the difference is small. Also, they are very similar in maintenance, with carbon steel being easier to (re)season.
For specific values and for better understanding the theory behind the heating of pans, read this article. For an example of somebody who has come to prefer his carbon steel pans over his cast iron ones, read here. (The part I mean is the four paragraphs between the picture of the pans and the "seasoning" heading, but the whole post is an interesting read too).