I'm on my third diesel now (2x 175, 1x 184, all AWD). I've driven the 2l petrol and it feels gutless in comparison - it may only be 20hp less, but it only has about half the torque. Having said that, I do 25k miles per year so the diesel is the better choice. For low mileage, the petrol avoids any of the carbon buildup issues (and, as Anchorman says, that may not be an issue on the 184 adblue engine anyway, it's too soon to tell. One other point, though, the official MPG figures. The petrol engines real mpg isn't much lower than the official, but the diesel is much lower. In reality, the diesels do around 40-42 MPG for the higher output engine.
Alan