We are putting one on now (new style 4" x-series). So far so good, I am doing a bunch of other stuff at the same time so its a extensive project. As soon as I get her on the road, I will post on ride quality and how well it works. I just stabbed the trans tonight so I haven't even ordered a drive shaft(s) yet.
They are using a johnny joint style joint and claim to have rebuild parts for them as well. The kit has all 8 new adjustable links each with a joint on one end. The lowers are very beefy and a BIG improvement over the older style x-series. I went with the upgrade shocks (2.2s) so with any luck they will help the ride.
Regretfully, in may haste to get started I didn't measure height before tearing her apart. It had a 3" lift (coils, Rancho 9000s, etc...) when we started so I was curious as to the actual difference. Oh well.
When we get finished, we will have some leftover stuff to get rid of (3" lift, 5 32" Yokohama ATIIs on factory alu wheels, t-case drop, new 4" lift shocks, dana 30 axles, etc...). All located in southern Wyoming.