A year or so ago, I decided to convert the fork on one of my bikes to a threadless carbon fibre. I had no experience with threadless headsets. The headset that I used was the Cane Creek (c2?). Since the conversion, this bike has probably been ridden 1600 miles. I've not had any squeaking of any kind. But I do agree in general that a threadless headset seems considerably more touchy about how it's adjusted. When I adjust it, it normally takes a few attempts to get the feel just right without any headset to steerer tube looseness. The other road bike that's in my garage is a threaded steerer tube fork, and as most of you know they're much easier to adjust.