Darkfighter v Standard with higher MP

Hi, I've an option of 2 possible cameras for mounting in the front garden (it will on the soffit high up - not ideal height but the only location available). It will cover garden and cars.

Dilemma is a 4MP Darkfighter (DS-2CD2345FWD-I 4 MP - "5" meaning Series G1?) v a 6MP Standard G0 model (DS-2CD2363G0-I 6MP)
Not sure which benefit (Darkfighter or higher MP) is the best option. I have no issue with bandwidth or storage capacity.

Already running 3x DS-2CD2343G0-I 4MP on my system. The new...

Darkfighter v Standard with higher MP