I have the 4" skyjacker lift and it's ok for how cheap it is.. The ride is fine, several people tell me I have a nice TJ and it gets me into places a stock TJ would have problems. However, I am slowly replacing the whole kit. It got me up high enough to get bigger tires, play off road and learn that I want better. If you have the money to do better then go better, if not... it's acceptable.
I have the zone 4" kit. It seemed a little higher quality than the rough country I put on my previous jeep. It rode a little better (smoother) too.
I think that the zone lift (which included ca's, shocks springs, t-case drop, linkage brackets, pinion cam washers and track bar relocators) was a better quality wit for the money I paid for it (400ish).
I have had it now for about 6 months and no problems yet.
Be very careful with the wife mod. Uninstallation can be extremely expensive. Wife mods have been known to take the Jeep and all other mods during the uninstall process. Also, make sure you service your wife mod properly as often as humanly possible. Wife mods not properly serviced may malfunction or uninstall themselves at any time.
Have the 4" x series short arm and it does everything I want it to. The price was good and the alignment was very close after fallowing the directions. Everyone here has the right idea... research and patience are your best friends.
I have the Zone 3" kit and love it!!! Next on the list are a full set of Currie control arms...or rokman...Savy
Building my junk with more junk, so Im always on the look out for more junk....Free to cheap preferably. :D
My junk http://www.jeepforum.com/forum/f22/survivor-project-driveway-frame-swap-33s-build-1280626/index3.html
I have the 4" Zone lift on my LJ with 40000K and no issues at all. It rides much better then stock. The parts work well for the price and the bushing are holding strong. I wheel alot of rock but it is pretty mild. For the price it has worked very well. I live in Ontario Canada and the powder coating is still strong after 40K. The only bad thing is no upgrades or plans to upgrade. So im building my own.
The shocks are the same as BDS as are most of the parts as far as I was told, but you dont get the life time warranty. Appearance and bushing wise better then rubicon express.