First, buying a faucet from the website-by-the-bay is a crap-shoot. You don't know if any little pieces are missing, and you have no one to turn to for warranty and parts issues.
I don't have any preference for any brand as far as the mineral buildup. You have very hard water, and without a softener, you will have ongoing problems.
Delta's are easy to service. Any brand of pull-out spout is going to have issues in the spray selector with all that hardness.