Emerald Club is similar to Hertz Ultimate Choice - basically, you get to pick from any available car that's in the area designated for for your status. To participate, book a midsize. No, you do not need to stop at the counter. First time renter may have some additional steps at the exit booth if they need to verify your license / credit card but otherwise should be hassle free.

If you need an SUV, the best advice is to book one because there is no guarantee they'll have anything specific on the Emerald Aisle / Executive Selection. If you book an SUV you get to pick from the "SUV Reserve" area.