So far so good. We got the base model with the 4-cylinder engine so we could get the 18 inch wheels instead of the 19+ wheels on the 6 and V8. After driving the 95 horsepower Dormobile or even the 180 horsepower Range Rover, even the base Defender engine with a tad less than 300 horsepower is a rocket. The low end torque is good, although there is a little bit of turbo lag. We don't notice it off pavement at all, it is only when turning left in traffic and you want it to go now. Left-foot braking gets around this issue. We didn't get many options, but made sure we got the locking rear diff. That came with the upgraded "off-road" tires, which really aren't that great - we got a flat on our first off-pavement trip with only 350 miles on the odometer. The dealer said that was a record for them. We swapped them out for 5 BFG ATs and haven't had a problem since.
Since then, we have taken it on a number of trips and stock it performs in the dirt and rocks as well as our 1992 Range Rover does. The Range Rover is not stock - it has a 2 inch lift, 32 inch tires, and a Quaife torque-biasing diff in the rear axle and a Tru--Trac in the front. On the paved roads there is no comparison - the Defender is quieter, faster, goes around corners better, and gets 50% better fuel economy, which is 18-22 miles per US gallon vs 11-13. The ride is about the same - the RRC has RTE +2 springs and Koni Raid shocks which ride very well and laugh a the speed bumps in my neighborhood.
In the first 10,000 miles we have only had a software problem, which was fixed with an update. The engine auto-stop-start shuts the engine down at red lights. When the light turned green and I hit the gas, it would throw the gearbox into park. There is an auto-stop over ride button on the dash when got around this problem until the software update was performed. Now it is perfect.
Changes we have made so far: We added a Front Runner roof rack, a Maxtrax holder, a folding table to the rear door, a Comet
CA-2X4SR ham radio antenna, and are trying to figure out where to mount our Yaesu FTM-300DR radio. In the meantime, we run a handheld attached to that antenna.