I can't imagine why anyone would spend more than the nominal price this shuttle charges to go round trip to and from the strip. The minute I landed I was able to "check-in" to let them know I was there. It took a few minutes to get my bag, and when I went to their station outside, a guy came to call my name knowing that I was probably ready to go. Ride to the hotel probably stopped a couple of times, but hey, Vegas is about sightseeing, so I didn't mind, it was still incredibly close and quick.
On my departure, my email from them had already advised me that I needed to be ready to be picked up at 11:30 (based on the flight time that I input). The shuttle was delayed about 5 minutes, and I received an email warning me of it. I'm pretty sure I could even track where they were on a navigation screen, but I didn't care, I had plenty of time. Once the driver got there, once again, he called me out by my name. Both drivers were super nice and chatty, and the attendant (I wish I'd gotten her name) at the station at the airport was INCREDIBLY helpful. She walked up to people one-by-one asking if they understood the process, not the other way around.
For the price I paid, I would've been satisfied with a shuttle service that's "first-come-first-served every 15 minutes." But for the kind of personalization and actual honored reservations these folks offer, it is simply DIRT-CHEAP. I'm not easily impressed, but this service really is worth it 100%.