I recently bought a new Mazda 6 tourer and had to make that decision.
I got the biggest petrol engine available (2.5L).
It was £2,500 cheaper than the equivalent diesel.
It gets 40 mpg and will take 4 years to cost that much more in fuel.
Cheaper servicing.
Same power but less torque. Enough for me though.
Quieter, and warms up quicker.
I feel much happier doing less damage on short journeys (I do long ones too).
But no regeneration, adblue or any of the engine/particulate problems that diesel brings.
PS We have a newish diesel CX-5 too and I know which one I prefer.