User experience of agile project: I have never known a project to develop at such a rate."

The unfortunately named Extreme Programming (XP) is a development focused methodology. It comprises of 12 basic rules and techniques that govern and control your project providing a disciplined rather than controlled environment.

XP is a natural process which will be accepted rather than enforced. Intuitive techniques such as continual customer collaboration, short iteration planning, refactoring, test-driven design, simplicity and prioritisation are readily adopted, particularly by development teams, and as such XP has gained strong support from the development community.
Some people see a weakness of XP being its developer focus and minimal management view (of the 12 rules only 3 relate to management). However, when embedded within an iterative, Agile process that has more management focus (e.g. DSDM, RUP or Scrum) it can deliver significant benefit at relatively low (or zero) cost and low risk.
IndigoBlue has a long held view that incremental delivery, and the supporting incremental strategy, is core to the success of Agile management. This tenet is the basis for our governance framework and our approach to managing Agile at scale. Last week I was presented with an illustration of this in the shape of one of our customers that has recently piloted the use of Agile in their office in the States.