Lately I have been back to back testing wheelsets, one made up of Enve AM rims laced to Chris King hubs, the other Bontrager Rhythm Pro rims laced to Hadley hubs. This pair of wheels is my own, the Enve/King's are from the NZ distributor.
First up there is about 130 grams difference between the two wheelsets. This is mainly in the rims, the Enve's being lighter carbon rims than the Bonty's Scandium alloy. Enve rims are 30mm wide, Bonty's are 28mm.
Chris King products have a great reputation for being well made and lasting a long time, so their hubs have been made in the same vain. Hadley hubs are little known, but come from a surgical tool maker in California that likes to make high end hubs in their spare time. The Hadley hubs sport a freehub body machined from solid Titanium, bearings are regular sized 61804's, (or 71804 angular contact) except for one in the freehub that Hadley make themselves. The hubs can be opened up and serviced very easily using two cone spanners. The King hubs are also easy to open up, but the bearings are their own sizing and made of stainless steel, which is a little soft for hub bearing use and will grind out pretty quick when they get water contamination. King has their own take on a freehub clutch system preferring to use gears instead of the normal springs and pawls as do the Hadleys. The King freehub body is made from alloy and is showing wear after 6 months use. The Hadley Titanium freehub body shows no wear after 3.5 years of use.
So to the ride. The Enve's have had their fair share of hype since coming on the market and you would be lead to believe that carbon rims are the way to go for everything these days, well that ain't so. There is a point when a wheel can be to stiff and the Enve's are that. Too stiff for fast technical riding. I have a test track that's 4 k's long, has many tight switchbacks up and down, berms and some nasty rock gardens with soccer ball sized round and square edged river rocks. Try to skip across these rocks at speed on the Enve's and it's like being in a pinball machine. I let 10psi out of my forks and over a few laps had my tyre's down to 21psi up front and 25 in the rear. Only slightly better ride, still pretty bouncy. The lack of vertical compliance kills your speed, because the rims don't absorb any impact, you get bounced around and lose momentum. In really narrow single track, around 150mm wide, they are a handful too. They make your bike's steering quite a bit quicker, but this is not what you want in the super narrow. On wide open smooth berms, great, really sharp handling, you can get some extra speed on cranking through corners. Compared to the Bontrager rims, the Enve's are way stiffer, faster in smooth corners, slower everywhere else that's not smooth.
The hubs are quite different too. The Kings are high quality, but they are no match for the Hadleys in speed and acceleration. There is a noticeable amount of extra drag in the Kings, both front and rear and the Hadleys are much quieter too, better for sneaking around.
So, that's my take on these wheelsets. Yes I might be a bit bias toward the Bonty/Hadley wheelset as these are my own and have been riding this particular pair of wheels for 3 and a half years, but I did expect to be impressed by the Enve/King wheelset and really was only disappointed, especially when the cost is almost double. Spend your money wisely and test before if you can.