solar in northern arizona?

System

I am considering starting with a solar water heater. There is pretty much only one guy within about 50 miles that I find that does this. I am in Cottonwood just outside of Sedona. He estimates the unit to run me about $5800. that is before any rebates. Does that sound legit. He is thinking about putting a unit on my roof. What about the solar water heaters that work in conjuction with my existing water heater to take advantage of the tank I already have?