I’ve always enjoyed reading about software development methodologies and approaches (my favorite essay is Frederick Brooks’ “No Silver Bullet“), probably less because I love software and more because it’s interesting to see how people, who are inherently fallible, translate their hopes and desires into instructions for an inanimate machine. When you mix the innate fallibility of humanity with the near-absolute certainty of the “right way” present in at least a few software engineers, you’ve got a very peculiar kind of theater.
When people ask me what I think about various software development methodologies, I can’t say that I have a super-strong opinion except that processes that are generally “agile” are good. Recently, I was thinking about this and dusted off a copy of Major Barbara, a George Bernard Shaw play (one of my favorites) that deals with religion. Adolphous Cusins (a not-so-sympathetic character in the play) says this in Act II:
I am a sort of collector of religions; and the curious thing is that I find I can believe them all.
That’s pretty much how I feel about XP vs. Scrum vs. your-agile-methodology-here. There’s a little bit of goodness in all of them.
(Photo: bust of George Bernard Shaw in the Reading Room at the British Museum)
Chad Dickerson's blog 
In my experience even though we have lot methodologies in hand ultimately many companies tend to follow gut feeling to cruise the project ahead. Methodologies in blue print goes to trash .Probably XP made it self a big hit because it is simple