I bought the Craftsman branded (kastar) 48pc set. Seems like I will only be using about 6 of the pieces, but I am giving them a pretty good workout as well as using the thread files a couple of times.
I pulled my front strut/shocks today and the rubber top that bolts into the strut tower had the nastiest looking threads. A bit of oil and one pass of the chaser and the threads were clean and new looking. Thats maybe the best thing they do, oil, chaser, and blow off with high pressure air and the threads are completely clean.