David B wrote:
Only down side to them is that you've more limitation on altering the height of your bars.
For me that is a major down side. Changing stem height is very useful sometimes and flippin' difficult with threadless stems.
I have never had a stuck quill stem or seatpin for that matter so that point is moot as far as I'm concerned. The initial installation is only easier on integrated headsets and ongoing maintenance isn't really an issue with either in my experience. I'll admit modern stems are stiffer but that is not necessarily the headset coming in to play but rather the oversized hollow construction of the stems. It should be entirely possible to produce a stiff quill stem using the same technology. Modern bikes are slaves to the latest marketing maxim of "stiffer is better" - just look at Deda's 35mm oversized 'bars and stems - how much stiffer do we need to go?
Having said all that my main bike has a threadless system because it was a new aluminium frame and I didn't care either way about the headset technology - it was the frame design that was important to me. However, if I was looking for a new steel frame in traditional small diameter tubing like the Holdsworth I would go for a quill stem every time.