I'm thinking of using Brazillian Mesquite engineered hardwood floor, I've read several reviews online and while everyone says the floor looks fantastic nearly all say they are disapointed in the scratch resistance.

I was surprised by this since I thought this had a good Janka hardness number and also because the colour was solid through the wood, ie it was not really a stained wood color

So what effects scratch resistance and what would be a better alternative to Brazillian Mesiquite with a similar color?

The Janka scale, has nothing to do with finish scratching.

A scratch in the finish, is not a dent in the wood.

Kendallas,

I am wondering if you are purchasing a prefinished product or unfinished. If you are purchasing a prefinished product then ask what finish is on the product, hopefully an aluminum oxide finish. If it is unfinished you can determine the strength of the finish yourself with various products.