The choice depends on your tastes, preferences and the use you make of it! Some consistencies will be easier to use depending on what you want to do with it.
For example, if you want to spread honey on a slice of brioche, choose a creamy consistency. But if you want to use honey to replace sugar, in a yoghurt or a dessert, use a more liquid texture.
Yes! You can use honey instead of sugar. It will give a sweeter taste for less quantity, thanks to the fructose.
Every honey has a different taste and consistency, depending on the plants it comes from. As far as the colour of honey is concerned, this is simply due to the pigments in the plants.