Been doing some research and reading about hubs. Always thought CK hubs were the best but many people don't like / rate them. DT Swiss and Tune look good and get good reviews

Any thoughts as to which are the best hubs for XC in terms of weight and smoothness?

DT 240s are excellent. Simple, light, reliable, and easy to service.

Not cheap, but excellent!

Bearings were an issue a few years back, but run on stainless cartridges now, and I can't really fault them.

Hopes for me. Only used shimano otherwise tho but I have no issues with hope pro !!s and I believe they are fairly light.

Forgot to say – Tune are a frickin' nightmare. Mostly as they omit the bearing spacer to save weight, so perfect bearing preload is critical to avoid side-loading the bearings.

As you've found, Kings aren't very light and require a reasonable amount of maintanence to keep them going, they have a lot of drag in the seals too.

DT240s would probably be my shout, the 190s are lighter, but are truly extortionate, you could fit full ceramic bearings to the 240s for less money than the 190s, and they'd weigh less and run more smoothly.

Tune are good, I'd avoid anything but the basic King/Kong though, I had a Kong Superscharf and it had a carbon axle which meant you couldn't service it yourself, every time the bearings went (which was twice in the 18 months I had it) you had to unbuild the wheel and return it to Posh Bikes, which was a nightmare. The Prince/Princess are the same. I believe there is a way of getting into the Prince hubs, but it's a bit heath robinson, and they're also seriously expensive.

Then there's the new Tune hub, Dezibel or whatever they're going to call it, which is phenomenally light, and probably has a price tag to match!

If I was custom building an XC wheelset I'd get XTR hubs every time. They're not the lightest hubs out there but they're not bad weight wise and they'll last forever. Cheap and easy to service as well (the once every 5 years that they need servicing).

Mate of mine had a Tune rear hub. It was worse than useless.

I must say I liked mine, except for the servicing issues! Would happily have standard King/Kongs again.