PRG stated the following back in 4/05:
"What makes a shock good or not-so-good is the size of the shaft/piston/body and the reservoir. A 9000 series rancho uses a 1.625 piston dia, where a DRE shock uses a 2.25 piston, this is like comparing a honda 4cyl engine form and '83 civic to the 5.6l in your titan. The adjustablity is more of a gimmic (sure you can feel the difference, but take a bit hit, and you'll still blow right through the travel), especially the way they advertise it, here's why. The adjustment does very little to control compression damping (the valving on the piston does that) and that is what is needed to change to handle "jumps" or even big hits. The rebound will effectivly change the ride, but the funniest part is that the faster the roubound the better the ride off-road, this is the exact opposite from the marketing they sell you with the shock." - End quote.
Now if you are the type that will never truly off-road your Titan, the xxx might be enough for you, and might even last the life of your Titan.
But even so check this out. It's a link that shows the difference between a Rancho and a true race shock, (click on the left thumbnail):
http://www.titantalk.com/forums/327757-post16.html
BTW- the Donahoe Racing coil-overs, (DRE), have a lifetime warranty, and come with a much better coil-spring than the stock off-road Ranchos that many aftermarket shocks will re-use. Re-use of the coil will also run the installation costs way up since springs need to be compressed for disassembly and install vs. the DREs that are a bolt-on complete solution, that is as easy or easier than Greg's leveling kits' installation.
So with labor and just one replacement, the xxx will cost as much, and not be nearly as off-road worthy as a Donahoe's, (or the Fox coil-overs that are used for the Pro-comp, CST, Fab-tech, or Rancho lifts).
There are not that many things you can purchase that you will like more and more - as time goes on. The DRE coil-overs are one of them, IMO.