From past posts I've seen shuttles are usually per person and around $60 each way. And then you're tied to leaving on their schedules which sucks, especially if you want to ski on your flight day. I paid $200 for 4 days with a jeep wrangler a couple weeks back out of SLC which easily sat 3 plus gear.
My friend just recently took a shuttle to Copper Mountain with his 13yo son. His son sprained his ankle two days before the trip. Given everything was prepaid, they went anyways. I had suggested to take a day trip out to Glenwood Springs to go to the hot springs and see the drive through the canyon. Without a car it was a no go. Instead they hung around the condo for 3 days while the dad snuck in a few runs here and there.
Also, for the convenience of grabbing groceries or taking an emergency trip to the drug store, you can't beat having a car.
I guess if you were right in the downtown core of PC, it would be a pain to pay to park a car, but for a good majority of the lodging options in town, not everything is walking distance.