Pros (compared to the i version of the same vehicle):
- Greater forward traction in inclement weather and on sub-optimal surfaces
- 10 mm higher ride height ( a positive in deep snow and for clearing uneven surfaces)
- Faster 0-60 times typically 0.1-0.2 seconds faster to 60 km/hr
- Able to put power down slightly sooner when exiting turns
Cons (compared to the i version of the same vehicle):
- Reduced fuel economy
- Heavier curb weight (~ 200lbs of difference)
- Higher drive-train power loss ie. the amount of power that is lost from the crankshaft of the engine to what is put down on the road
- More wear items that need to be maintained and serviced and could potentially break down ie. 1) transfer case 2) differential for the front axle 3) drive shaft connecting both sides of the transfer case
- Harder to access certain items under car due to more components ie. bleeding the clutch is impaired due to the placement of the additional drive shaft
- Reduced number of available mods ie. certain exhausts will not fit an xi along with down pipes (in my opinion of 90% of available parts and modifications that work on an i work on the xi)
- Inferior suspension dynamics and options ie. sport and m-sport suspensions are not available on the xi even though the m-sport package was ordered in its entirety from factory.
- Reduced ability to "get the back end out" and over-steer
Ultimately it would seem that you are trading a lot to have better traction for 12 months of the year and that would be entirely correct. In my opinion all of the 'cons' aside from the suspension characteristics are completely livable and do not pose such a monumental difference when driving two similarly equipped cars back-to-back. The x-drive still allows the driver to have considerable fun and rotate the car when desired, which can be easily achieved by simply disabling dynamic stability control (DSC). The desire to have a car that would provide me with year round go anywhere capability, whilst having the most fun in every season, led me to choose the xi. All I can say is that in the past 2 years of ownership I've had to dig multiple cars out of snow and ice, never once was it my car, but for those that live in California, forget an xi option even exists.