It is no slouch -- off the starting line it adds the torque of 3 different electric motors to the 300+ HP engine. Like the predecessor models, it has all-wheel drive, but the rear wheels are electrically driven. There's no mechanical coupling of the gasoline engine to the rear wheels.
It also uses the electric drive on the rear to create drag on the inside wheel and drive the outside wheel when turning, even when not accelerating. As a result, the car feels much more nimble than its 4,000 lbs.
MPG is 28/32: not stellar, but a substantial improvement over the non-hybrid version's 20/31. At current gas prices, I'm not sure it's worth the additional cost for gas mileage alone, but there are a number of other features unique to the hybrid version.
I would prefer the 650hp 2015 Corvette Z06 or the 707hp 2015 Dodge Challenger Hellcat.