Very smooth

Very good.

Picking up the car was quite convenient, located right across from the Hilton Union Square. However, Thrifty and Dollar have merged, so the line was somewhat long. But there were plenty of staff, so the queue moved rather quickly. Returning the car was even more convenient. We returned it in Las Vegas at a dedicated car rental center. Just follow the signs all the way in. You don't need to wash the car; just return it with a full tank of gas. There are many gas stations nearby, and the prices are fairly cheap. The car return location is not inside the airport, so you'll need to take a free shuttle bus to the airport. It's very convenient and takes about 10 minutes to get there. The driver is very nice and helps with the luggage, so you can give a small tip.

Charged more on the spot under the pretense of additional taxes.

Like: Picking up and dropping off the car was quick and easy. The car was in decent shape and had low miles.
Dislike: Evidently the on line rental service I used was a European company. The rental agent told us we needed an international license at first. Then told us he would let it slide. Really? What difference did it make who set the rental up? And when I am getting the car you are going to try to charge more?