K.S.
E., We just bought the 5.31 at christmas time and I love it!!! We considered the 5.35 but I just couldn't spend the extra money. I never use it on the highest incline. (It's really high already, like a stair stepper)
I have always liked using the arms at the gym, but to be honest, I don't miss them! My husband does light wieghts with his arms when he is on too. I would say get the 5.31 and save the money. Good Luck and Enjoy!!!