Easy rental experience in USA (Denver).
As we had rented (through Sunny Cars) from Alamo earlier, they already had all the driver details in their systems and we were ready to go in just minutes.
For one-way rental they had limited cars available, which resulted in an upgrade from midsize SUV to fullsize SUV hybrid 4x4, at no additional cost, because that was "closest to the agreement" for one-way rentals.
Be aware they often try to upsell a full tank of gas so you can drop off empty. If you can plan to drop it off nearly empty then this can work out, otherwise you pay more than just filling up yourself just before driving the last miles to the dropoff location. They prices per gallon when they fill up are insanely high but the prices you'd pay for the full tank upfront are listed as excluding taxes so not even as good as they seem.
Overall the process was very smooth - from booking to pickup to dropoff. Didn't even need the voucher but only my passport. That was different from last year - back then they had to manually recreate the rental agreement so this was a huge improvement!