Jodes, the reason why all of the good kitchens on Pinterest look like they have been photoshopped is because they have. Some of the larger manufacturers (such as Ceaserstone) have a great sample chip service where you can order samples for free to be posted to you. Your perception of your white benchtop will be influenced by the other colours in your kitchen such as the splashback and cabinetwork, as well as the lighting, so making your final decsions at home is always the best.
If you are looking for whiteness don't consider a natural stone for your kitchen as these marbles are softer and more porous than the reconstituted stones. You get a more durable surface that is easier to live with a white reconstituted stone.
Never base your selection on a photo or an internet image as they are indicitive, and these images lie! Finally when ordering a reconstituted benchtop there is a fair bit of back and forth for the stonemason. A good stonemason will visit to get an template for your kitchen benchtop, then return to his workshop, then cut the stone to match the template, then revisit to install. If you are in a regional area it is worthwhile finding out what brands your local guy will work with. There is no point is making a selection from a brand if the nearest stonemason who will work with that brand is 500kms away!
Best of luck,
of Dr Retro House Calls