The ITA tool is pretty awesome from the mileage runner standpoint, although this is kind of a niche market.
I've used it for searches like, "find me trips between point A and point B that involve three segments on the outbound and two on the return, all on American."
When I wasn't trying to come up with some insane routing just for miles/segments, it still was better at coming up with routes/prices than whatever my old company's corporate travel service used. I would never let them book me anything once I found out I could take five minutes, look on ITA, and more often than not find a more convenient route for less money.
I've used it for searches like, "find me trips between point A and point B that involve three segments on the outbound and two on the return, all on American."
When I wasn't trying to come up with some insane routing just for miles/segments, it still was better at coming up with routes/prices than whatever my old company's corporate travel service used. I would never let them book me anything once I found out I could take five minutes, look on ITA, and more often than not find a more convenient route for less money.