It depends on the developers. Unfortunately, you can't just stick any two developers together and expect timely, high quality results. Not everybody is cut out for paired programming or even cut out for working in an agile development environment. Two things about paired programming that I think make it worth while are : (1) Cross-training between developers; and (2) Real-time peer reviews. Cross-training will help to strengthen the skills of the team as a whole, and real-time peer reviews can eliminate the need for formal peer reviews. I've learned more from my peers over the years than I ever learned at a technical training.
