You own both? It sounds like you have overlooked the facts for a more emotional approach which is fine, as long as it's not presented as reality based.
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Emotionally speaking, I LOVE my Disco2!!!
While the LR3 does weigh more, it can gain rather high ground clearance specifically due to the air suspension where the D2 requires quite large tires, which require more than basic 2" lift to equal the same minimum clearance under the differentials. Breakover however is way higher on the Discovery 2 due to the frame design. OME 2" lift not requiring other modifications, allows a 31.5-32" tire, which WILL rub on the front trailer arms at full lock further reducing it's turn radius, further from what was already less than the LR3. As you know, turn radius is of use off road, as well as in tight neighborhood parking
Some of what you may think are negatives on the LR3 for certain uses, are in fact positives in other uses, such as while towing. Towing at the maximum rating is really an easy event with the LR3 due to it's 13" longer wheelbase, the air suspension equalizing things, and it's weight being less affected by the trailer or tongue weight.
Rear overhangs are pretty similar on them both, a little longer than a Land Cruiser but way longer than a G wagon.
For the $ though, that's another way to look at it. These days I see the Disco 2 as a wonderfully well priced value. So much vehicle for the low price with not too much to worry about. I still have about 18 months full warranty on my LR3 so I'm less "worried" but the truth is that there are more expensive things to deal with overall.
If someone came and said choose one, we're taking the other, I'd be handing over the LR3 key before they finished speaking.