For groups, a shuttle (up to 8 passengers) can be booked for around $150 total round trip (etransfers.com is recommended, or welcomepickups.com). ADO Bus is a safe, clean and reliable coach bus that regularly travels straight from the airport to PDC for $10-15 each way (you will probably need a taxi to get to your hotel from the bus terminal). For those who want more flexibility, we would also recommend renting a car at the airport (The Reef 28 and some hotels offer free valet). Please be aware that while the car rental itself is very inexpensive, Mexican car insurance is required and it can cost a few hundred dollars.
PDC is safe and very walkable, however taxis are reasonable for getting around. We've also arranged with a local transportation service - you can call ahead 20 minutes in advance to schedule a pickup (Angie Lievano - 984 1792193). Ubers aren't available in the city :(