...my own opinion, and it is only my own opinion, is that while there might be some extended lifespan in BB sealed units like the ones from Phil Wood, the more moderately priced ones, (even including the ones that are not bottom of the line from Shimano, but their slightly better offerings like the UN-55), go for so long that I am unable to wear them out. There are some deals on outdated square taper ones from Campagnolo, that you can find online, and the VO offerings are good quality, at about 50 bucks (more or less).

There's a practical limit to quality on these, because few manufacturers make their own bearings.

I know nothing about Chris King products, either headsets or BB's. The headsets seem a little pricey to me, for what you get. And you need a special extra tool to install them. Again, only my own opinion. Someone else will probably weigh in shortly.