Re: When it works it's very very good; but when it doesn't, it's horrid.
"Long ago, I was a programmer. Fortunately, I never collaborated -- it would have driven me mad. Your mileage may vary."
yeah, good point.
paired programming works ok if "I drive" and the other guy [whom I'm assisting in getting the project back on track, for example] has intimate familiarity with the details. Then I can focus my 'big picture' mentality on getting the solution, and make use of "the detail guy's" experience. [it's worked well a few times, actually]
but for day-to-day development, I wouldn't bother. just use it when it makes sense. it goes in line with the "mythical man month". 2 programmers working on the same thing might be worth 1.8 programmers. Or 10. YMMV.