In trying to appease people with a multitude of tastes, BMW M's plug-in-hybrid SUV flagship loses focus.

We've been anxious to sample a production version ever since we drove a development prototype last year. Now we have, and we're left wondering if there are a few too many ingredients in its mix.

Those hoping for a deep, V-8 rumble may be disappointed, though, as its active exhaust emits a raspy growl more befitting a V-6 (additional V-8 sound effects overlaid with an EV-like whir are piped through the stereo speakers).

Though far from harsh, the XM's ride is busy over small, high-frequency bumps, even in Comfort mode on the smooth Arizona pavement of our drive route. Sprawled out on the cushy rear bench (individual captain's chairs are not available) with its throw pillows and expansive 40.3 inches of legroom, we could feel a jitteriness filtering up through the chassis, spoiling the ambiance. Similarly, the flat rear seat's lack of lateral support means you'll need to brace yourself if your driver decides to have fun behind the wheel.

But as the pinnacle of the M brand, the XM is less a delicacy and more a mash of features that leaves a confusing aftertaste.