boudreaux said:Both have been around for awhile.. I really havent paid enough attention to know if there has been a swing toward the hybrid. Cdale has used the campy hiddenset(hybrid) or another makers variation of it since the caad5 introduction.Other makers misuse the terms integrated and internal so it can be hard to know what they are using and some have their own proprietary designs. I seem to recall more problems with some early specific headsets as the other poster mentioned,rather than a condemnation of the design.I really haven't heard of frames being trashed by either,but the hybrid would seem to have the potential for fewer issues,especially in aluminum frames or CF frames that used aluminum headtube inserts.
I checked with the shop where I purchased my frame (City Cycles - S.F., CA) about its durability using the integrated headset design. They said the frame's durability shouldn't be an issue, even though the lugs are aluminum. They mentioned Kline as a example of a frame builder using the integrated headset design for more than 10 years without incident (to your point above) on their aluminum mountain bike frames, and also noted that the forks used for these type of frames impose much greater loads on the frame's races than a road fork would impose. Lastly, and you also made this point, the high-end frames generally have much better milling than lower-end frames, and this helps to keep the tolerances very tight, lessening the durability concerns considerably.
All in all, they felt the integrated headset, for this particular frame, was not of any concern and felt that any good quality, high-end frame would be equally durable using an integrated headset. I agree that the evolution of the "hybrid" headset is probably a good example of improving the breed, but I must conclude that if executed properly, the true integrated headset design is still a viable and reliable alternative to consider.
-Wm.