It's okay.

Car rental services in the US are a joke, talking more is a waste of time. Strongly recommend avoiding renting.

Purchased insurance, but they still tried to upsell.

Why was I asked to pay another $175 upon arrival?

When picking up the car, the staff tried to forcefully sell us insurance. They refused to give us the car unless we bought it. I called the rental company but the representative was unhelpful and just asked us to sign the form. Eventually, we had no choice but to agree to an increased price from $459 to $538 (originally over $700). They gave us a Mazda 5 instead of the mid-size SUV we booked. We were only given four cars to choose from. When I pointed out our booking, the staff casually indicated all four were small cars. I had to insist it was an SUV before they acknowledged the four available. Overall, it was an unpleasant experience. Avoid using THRIFTY at all costs. Their shuttle service is extremely infrequent; we waited 45 minutes for one to arrive.