A car that's a few years into its current design is usually beginning to show its age, especially when it has as many serious competitors as Infiniti's M sedan does. The M outpaces that trend: The 2006 original took the field by storm and, relatively speaking, today's car is eight-tenths as terrific. In a segment whose players' strengths vary across many fronts — performance, technology, quality, reliability — the M emerges a competent choice across the board.

Infiniti sells two variants, the V-6 M35 and the V-8 M45. All-wheel-drive versions of both are also available, dubbed M35x and M45x. Ever since the brand dropped the larger Q45, the M has become its de facto flagship. As such, it's enjoyed frequent updates to stay competitive. The 2009 model sports an upgraded V-6 drivetrain, while the V-8 carries over with minimal differences. Click here to see a comparison with the 2008 model, whose review serves as the basis for this one.

I tested an '09 M35x, though I've also driven a 2008 M35 and 2006 M45.

• Going & Stopping
• Ride & Handling
• Styling & Quality
• Seating & Cargo
• Safety & Reliability
• Features & Pricing
• M in the Market