I think on the whole this car is better than Vipers. Its more upto date obviously as Vipers was done some months ago but the overall shape is more accurate on this one. The textures on Vipers do seem to be clearer, more clarity in them (less blurry) though.
One thing I would say is that the rear wing looks a little short in height. Its not set too low, its just seems like it should be a few inches taller as the upper elements seem too close to the gearbox area.
The front wing looks very nice although as others have said, it does look slightly too high although that may be the Viper affect. His looks slightly too low to the ground and using that for months gets you used to seeing that and when you change car everything looks odd - even if it isn't. I'd say the height of the nose is spot on.
One thing I would have done is make the guiding vanes around the front suspension the same blue as the cars livery (like it is in real life) and not use that carbon fibre effect. And because the rate of development in F1 is so fast those exhaust covers are now symmetrical and not assymetrical any more and both are white.
Its a great car though, its now my default Williams so that says as much......well until I see what Vipers FW25 version3 looks like and then i'll compare.