if silence is important to you, be aware of the fact that with a carefully-chosen lubricant inside them, very many hubs can be rendered virtually silent. Typically a semi-fluid grease in the pawls (eg on WI hubs) will quieten everything up nicely.
The Onyx hubs contain a thing called a sprag clutch which is a close relative of the roller clutch. It may (under very high torque conditions) result in a drive connection that feels slightly spongy. Shimano silentclutch hubs (with a roller clutch mechanism inside) suffered from this; I don't know if Onyx hubs suffer from this drawback or not, because I have not ridden them in very low gear ratios.
There are videos of how to repair their hubs on their website; you can get access to them but I do not think that the sprag clutches can be replaced or seriously fettled at the roadside in the event of any problems. [By contrast WI hubs can (pathetic grub screws in some models nothwithstanding) can usually be stripped fairly easily.]
I note with interest that Onyx offer a warranty against 'manufacturing defects' being five years on the bits they make, one year on the sprag clutches, and one month (
) on the bearings.
I think that any of these hubs may offer good service if you maintain and lubricate them properly (often). CK hubs that have been neglected can be very difficult to take apart without damaging them, and they are not alone.
cheers
