Never owned a Jeep, but have driven a few. One of my employees has two and we compare points frequently. Have had 12 Discos though, here is my opinion:

1. Disco seats are better, much more comfy on long trips.
2. Disco is 5000lb vs Jeep at about 3000 - I would rate safer and better for towing. Disco rated to tow 7000 lbs. Disco rides better to me, maybe personal opinion.
3. 00-01 Jeeps used a cylinder head very prone to cracking - you can google search it.
4. Disco has a lower cg, I think it corners better, lower probability of rollover. Very few Disco rollovers, Jeeps are pretty common.
5. Disco is aluminum body, will never rust (frame is a different story). Probably not a problem in Qatar unless you take it to the beach and drive it in the surf.
6. Discos do better off-road - stock to stock. Watch the Jeep vs Discovery videos on youtube.
7. Disco has significantly more cargo room.
8. Both have cooling system issues - HG, Jeep has a heater valve issue, Disco radiators. Both are preventable with pre-emptive replacement.
9. HP and torque are close by spec, but Disco torque peak is much lower, gives better seat of the pants feel.
10. Discos typically are more luxury oriented - Leather, power seats, sunroofs, power windows, high end audio, etc.

I am sure the guys on the jeep forums could come up with 10 reasons to buy a Jeep.

 

Oh, interesting on the LR3, I have been looking to add one of those to the fleet for a while. Don't have one, but have talked to several techs. Here is what I have learned so far:

1. 4.4 Engine is pretty reliable relative to Disco 2 and LR4/RR Sport 5.0L, but more complicated with dual overhead cams, chains, etc. if you do have problems.
2. Transmissions have been known to have problems, there is a solenoid upgade package and a BMW trans pan package that are recommended.
3. Rear parking brake system is problematic.
4. ALL of the dashes crack at the passenger airbag - no known way to prevent. (my wifes biggest peeve with this model)
5. More modern levels of audio, sat nav., abs/terrain control/stability control.
6. Prone to water damage of ECU (likely not an issue in Qatar)