I'll toss my two cents in. I owned a coil sprung LR3 for a while and have extensive experience with air suspension equipped models also. I have thousands of trail miles in both, and have spotted for and trained numerous LR3 drivers in how to wheel them off road (they are different from traditional vehicles).
You are the third H1 owner I personally know that has "stepped down" to an LR3. In their opinions, the pro's far outweighed the cons (primarliy in comfort and versatility), but the overall experience has been about the same. They are heavy, with similar vulnerabilities. The cost to own is less, but the maintainence time (just taking care of them) spent on both is about the same.
The LR3/4 is exceptionally capable. Off the show room floor, it is the most capable Land Rover ever built. However, it is difficult to "build them up" to be even more capable. A well built Disco II or Defender will exceed the capabilities of a stock LR3, but never in comfort or versatility. Nashville Rover made the observation that the LR3 rewrote the rules for Moab. This is true, sorta. The LR3's class leading traction control is amazing. Combined with an incredible turning radius, and 13" of articulation and nearly 15" ground clearance (stock, in Super Extended mode), it really does make "difficult" trails quite easy....on certain types of obstacles.
I wrote a Moab trail guide rating system for "Modern Rovers" (LR3/4, Sport, and MkIII), that rates the trails in difficulty particular to the capabilities and limitations of the LR3. With your knowledge of Moab, perhaps this will be helpful to compare to:
http://lr3tips.wordpress.com/2010/0...-rallys-in-moab-what-lr3-owners-need-to-know/
Durability is a whole other issue. The LR3 engine and trans have proven to be VERY good...once the software is patched up for the trans. Where I have seen issues in durability is in the suspension bushings primarily. They are made of peanut butter and they quite simply wear out regularly and quickly. Figure every 30,000 miles or so, you will want to replace them (if you are doing a lot of trail use). Another troublesome area is in the wiring harness connectors under the vehicle. They are sealed, but water gets in them, and causes corrosion. I would reseal all the connectors you can find prior to heavy trail use or any kind of regular water crossings.
Air bags have proven very reliable. I know of only one actual bag failure. I know of a few airline breaks (easily fixed on the trail). But the major issue is that the computer gets fault signals from the level sensors, and drops everything down to the bumpstops. Sometimes this can be cleared on the trail (holding the battery cables together), but often it can't be. A $1,000 faultmate computer is highly recommended for numerous reasons, but this is a big one and its quite valuable for this reason alone. The Faultmate is registered to your VIN, so you can't share them unfortunately.
Otherwise, the Electronics have proven very reliable.
The differences in capabilities in the LR3/4 are slight. The 4 offers a very cool camera package that allows you to see every corner of the vehicle, but that's somewhat of a crutch a good driver does not need. The 3 has unpainted plastic fender flares and bumpers that are much more durable in the bush. On the street, the 400hp engine in the 4 is sweet. The 3's 300hp is no slouch though. THey both run rings around all older rovers. THe wheel size is an issue in the 4. You can "downgrade" the 3 to use the V6 discs and fit 17" wheels pretty inexpensively.
I recommend searching the other LR3 related websites for more info. I listed them here:
http://lr3tips.wordpress.com/top-sites/
Don't forget the tires!
http://lr3tips.wordpress.com/2007031446-2/
(Nightmare Gulch, and easy trail, but I love this photo)
