Im just wondering, why is it that these manufacturers use non conventional headsets? Not all do but a lot use integrated or zero stack. My homegrown calls for the ICBM, which is like a spin off integrated. Im very happy with my ICBM, but i dont see any reason why these companies cant use conventional. Can somebody englighten me, whats the advantage. Or at least whats the claimed advantage

Zero stack is useful for the longer travel single crowns. Reduces some of the stack heigh making the front 'shorter'.

I hate integrated. They blow.

I ran a zero stack with my previous frame and i liked it as well. IM not sure how well i like having bearings directly contacting frame. But i know for my ICBM those were some big ass bearings, never seen so large bearings for a headset before

Integrated sucks. Proprietary integrated (ICBM) sucks worse.

Zero Stack (aka Internal or semi-integrated) is far superior to integrated due to the fact it uses pressed-in cups.

Zero Stack is nice for a couple of reasons.

Like Maelstrom stated, it can help reduce stack height.

A couple of product managers I've talked to say their instances of headtube ovalization has been severely reduced and eliminated after switching to Zero Stack headtubes.

Also, the larger headtube diameter provides more weldable surface. This allows stronger frame junctions and easier connections to oversized downtubes without relying on severe tube manipulation to pinch the end into a conforming shape.

I'd like to think given some of those benefits, Zero Stack is here to stay. With King on board with their slightly modified Perdido headset, even reluctant conventional holdouts don't have much to complain about (they just need to find a shop that has the reamer to oversize their ZS headtube the required amount).

why does the ICBM headset suck?

I hate the idea of drop-in bearings in a mountain bike frame -- if something gets a little loosey goosey, it doesn't take long to take the head tube out of round. The proprietary nature of ICBM is even worse. I think Cane Creek is selling a ICBM replacement currently, and it'll be interesting to see how long they continue to support the dwindling number of frames using it.

If I can't put a King on it I don't want it.

I dunno though, when i was pressing in the bearings it wasa really tight fit, like as tight as if i was pressing in regular cups for a conventional headset. I just dont see it getting loose, i check up on it every so often though