Just came from a 3 day stay at PortAventura Resort, and I can definetely say that Shambhala(in PortAventura) and Red Force (in Ferrari Land) are the main rides you have to experience. Shambhala was my first B&M and my first Hypercoaster, and it was by far the best thrill value of any coaster I have ever been on (talking in reference to all Australian theme parks and Thorpe Park). Red force is fast, tall, and it will take your breath away. I recommend buying an Express ticket for Ferrari Land, as it includes a one-use Express to all major attractions for €20 per person (totally worth it). Red Force was a walk-on with the Express, and the line was 70 minutes long. Red Force uses Intamin's all new lap bar system, which really lets you feel the forces.