I own many bikes and only 2 Chris King headsets. They are perfect, and seem to have eternal life, but get more expensive every year. Cheaper alternatives seem unworthy of the money.
Most my bikes get headsets I happened to get a deal on. Deals are scarce for me now, but I came past the AHeadset offering on the On-One website, and had one thrown in with my order. 10 Great Britain Pounds, for a headset used on a bike that costs 400 Pound, you can't expect much.
The headset is very basic obviously. 2 identical steel races, non-identical cups, caged ball bearings, plastic top cap. Not exactly King-competition.
However, 120g for the complete set, including star nut, 30mm steel bolt, and the 10g top cap.
Pretty low stack too, ~23mm.
When I swap the plastic top cap for an alu Cane Creek I had laying around, I drop 2g and have a 118g headset. Possibly the lightest I own. It needs loads of thick grease though, so arounds 120g when mounted. Not too bad, right?
If you have a commuter bike, spare race bike, or like we have here : Beach Bike, better to trash this one than you King.
I should take the King from my Fisher SupCal29, it will soon be ridden on a beach again, and sees loads of foul weather anyway. It survives because it's a King, but may better be saved for a nicer bike that will be appraciated more, or ridden in condition I appreciate more.
If this headset dies after a year (I tend to get many years from this type of headset, as I have many bikes to chose from), a King will have to last ~8 year plus interest. If a bike should ever get stolen, better with this AHeadset in it than a King, I figure.

Headset allow the fork to steer, and have to do so without play. Even most of the cheapest ones do that just fine, greased up properly.

Sorry if I bored you, you were warned!


PS. to off-set this nice weight-loos, I got especially a really nice On-One Mary handlebar. 315g, but soooo worth it over any flat or riser bar! 200g of weight cannot make up for ergomical prefection vs. a bad idea from the 70's.