The Model X might be the greenest—and fastest—way to tote up to 7 people over hill and dale. In our test the P90D went from 0 to 60 mph in 3.3 seconds and has a 250-mile range; Tesla says the P100D hits 60 mph in 2.9 seconds and has a 289-mile range. The 75D and 90D have 238 and 257 miles of range; both are slower to 60 mph. The X is actually practical, with all-wheel drive, a high-tech cabin, and the striking but fussy Falcon Wing doors. Tesla’s Autopilot semi-autonomous driving is optional.