The muscular Armada isn’t just roomy, quiet and comfortable like you expect big SUVs to be, it’s also surprisingly fast, with nimble handling and a very smooth ride.

Walkaround: The Armada is based on Nissan’s big Titan pickup — arguably the best truck on the market right now. Like the Titan, it looks tough, with aggressive styling to match its commanding size. At nearly 207 inches long, it’s about a foot shorter than a Chevy Suburban and nearly as long as a Ford Expedition. It’s offered with rear, or 4-wheel drive, and features true low-range gearing for off-road driving.

Interior: The Armada is available in three trim levels: SE, SE Off-Road and top-line LE. But no matter what the trim level, it boasts Texas-size interior room, with seating for eight, and offering an elevated third-row seat. The second and third-row bench seats fold almost flush with the floor, greatly enlarging the cargo area — without removing the headrests Optional second-row bucket seats also fold flat, as does the front passenger seat.

Instrumentation is the same amber-lit, easily readable, analog set used in the Titan, as is just about everything else inside, from the unusually large door handles to the large, well-placed and simple climate and audio controls.

There’s also lots of beverage holders and storage areas throughout the Armada, including a convenient deep well between the front seats.

Because of its height, getting in and out of the Armada’s first and second-row seats demands full use of the fairly wide running boards, plus some extra effort. But that same height also provides “King-of-the-Road” visibility and feel from the comfortable driver’s seat. Rear visibility is helped by large outside mirrors, and the rear windows roll all the way down.

Like all third-row seat SUVs, getting back there takes some nimbleness, but once you’re there, the seat is fairly comfortable for adults. However, folding that third-row seat back to its regular position requires climbing into the cargo area or entering through a rear door.

The two-piece tailgate is handy, but the high load floor can make it difficult to load and unload cargo — especially if you’re short. With all seats in their normal positions, cargo room is modest, but more than generous with them flipped forward.

Options: The entry-level SE offers enough standard equipment to please most people, and even includes a rear-obstacle detection system, and power adjustable pedals as well as heated front seats and second-row buckets with a unique removable center console. The optional ($600) power tailgate is also only offered on the SE. The SE Off-Road adds an off-road suspension and skid plates to protect under-body components when driving off-road.

Extras include a DVD rear-seat entertainment system, navigation system and satellite radio, which I understand is the only one offering the choice of either XM or Sirius. There’s also a sunroof package costing between $1,000 to $3,350, depending on the trim level.

Safety: While big SUVs appear to be among the safest vehicles simply because of their sheer size and weight, the Armada features plenty of standard safety equipment, including supplemental curtain airbags for side-impact and rollover protection for all seating rows. Side-impact front-row airbags are standard for the SE Off-Road and LE — optional for the SE.

Anti-skid and traction control systems, plus anti-lock brakes with a brake-assist feature for certain stopping in emergency situations, are also standard.

Under The Hood: Power is delivered by a sophisticated, 305-horse, 32-valve, dual overhead cam, 5.6-liter V8. The engine produces outstanding torque, and with the optional towing package, can haul a class-leading 9,100-pounds.

The Armada is surprisingly fast for its size and weight, doing the 0-to-60 drill in about 7 seconds — making it among the fastest SUVs of any size.

The engine is mated to a responsive five-speed automatic transmission that contributes to that outstanding acceleration — upshifting like a luxury sedan with quick downshifts.

Behind The Wheel: You wouldn’t guess it looking at the Armada, but handling is downright sporty for a large, non car-based, body-on-frame SUV. Curves can be taken smartly with very little body sway and steering is quick and responsive. Acceleration, as we said, is outstanding with a smooth ride courtesy of Nissan engineers who substituted an independent suspension for the Titan’s rigid rear axle. The brake pedal also has a nice linear action, and stopping distances are short.

The transmission allows the engine to loaf at 75 mph, and has tow-hauling modes for enhanced performance and fuel efficiency — besides a first-in-class J-gate shifter for better control when towing, or in icy conditions.

All that weight and power has a price: an estimated 13-mpg/city and 18-19/highway. On the plus side, it uses regular gas, and the 28-gallon tank gives the Armada an acceptable highway cruising range.

Whines: The height makes cargo loading and getting in and out a challenge for shorter people, who may also face issues with soiling their clothes in certain situations.

Bottom Line: The capable, rugged, yet civilized and comfortable Armada makes Nissan the new Sheriff in the full-size SUV market — one that deserves to be making Ford, GM and Toyota very nervous.