Recently, in a course of a training session, we touched ground on what seems to be an interesting topic to me. One of training attendees raised a discussion related to pro and cons of different processes. In order to prevent another holy war I warned everyone that it scarcely matter what process people do use. What really matters is whether they know how to use it. Fool with a tool is still a fool.
Same is true to the processes. We have invented several big-name process as well as dozens of not so famous ones, however we keep looking. Why? - Because we are not satisfied with the results. Because we think that things could be organized better. And all we do in this intention is going cycles around several simple ideas (think ahead, do just enough, think before doing, think after you are done, observe and make corrections). All the process that I know of, are about these concepts, wrapping them in different objects, providing different interfaces to the user. Though the ideas behind stay as simple.
If we all use the same underline ides why some are successful and some are not? The answer is not in the plane of definition but it's in the plane of implementation. Do you remember that saying above? ;) The process is not a panacea. If you expect that a weak, diseased organization wearing a CMM hat will do much better then you are deadly wrong. People are what make processes to work or to fail. People are undermining it by doing thing "slightly different" or doing "just opposite" only because they think that they know better. Just look around and see if there are any of those characters right beside you. And start correcting things right away. Start from yourself ;)
P.S. I am not saying that all the processes are equally feasible for all teams. No. I only was speaking that nearly all the processes are GOOD and COULD HAVE BEEN WORKING if they were applied correctly. Anyway, the process is always better than no process at all. If it's your case, you know where to start! :)