I use Deep Crystal for washing tires and wheel wells because it is cheap and I use NXT on the rest of the vehicle to combat hard water. Plus, I love the smell and how much it suds.
Because I mix a bucket with about 2 gallons to wash the tires and wells and then pur that out to mix up one for the paint, I felt like was wasting a somewhat expensive wash (NXT). So, I grabbed some Deep Crystal for that job.