I'm going to use both.
I have ordered 4 'Bigfoot' models and next order I place will include a 'Nighthawk'.
I originally liked the look of the 'Bigfoot', now though, I am not real keen on the look of the Mortar on its back. So I am going to do a bit of converiosn work on two of the four that I have ordered. The game stats will remian the same however the look will be different. I am replacing the Mortar with a cool looking missile pack and I am keeping the hands and mounting some weapons slung under the arms. I have ordered all the various bits for the conversions.
The other two 'Bigfoot' models will become an entirely different version (another Marauder that I have designed myself), the reason I am using this particular model as a base is because I really dig the blocky looking shoulders of the 'Bigfoot' model.
When I get the 'Nighthawk' I will use it as is as I am happy with its look.