It depends on the client I have but personally I like the cream more. Not only does it cut down blow dry time, thermal protect but it's also good to not shampoo a style for two days because it's like a dry shampoo and holds a look
I've used both and prefer the cream to the spray. They both work amazing as a styler and heat protectant but the cream gives you a softer and silky feel and I feel like the spray gives you a more textured feel. Also both cut your blow dry time down.