In order, the treadmill is the best, bike is second and elliptical is definitely third.
Running on a treadmill is the closest thing to simulating actual running, and you’re getting the most complete full-body workout with the least restricted range of motion.
On a bike, even though your motion is restricted, you’re still using natural body movements, and the positioning goes along with your natural alignment. A bike workout such as a spin class, with loud music and a motivational teacher, can be an extremely grueling workout!
The elliptical restricts the range of motion resulting in short, limited and unnatural movements, though it is still a worthwhile option as a cardio workout.