The only real difference is the camera. The drone itself is the same.
It's more a question of what do you want out of your drone. If you're aiming strictly for photography and especially daylight, then the Zoom will likely give you everything you need. Even if the camera sensor is smaller, with huge amounts of light available during the day, you will be hard pressed to notice the difference. You are also likely to enjoy the flexibility of having the optical zoom on the camera (which does not exist on the Pro).
The Pro is more of a device for videographers or night photographers. Zooming optically is not a feature that filmmakers utilize (other than the Hitchcock'esque effect the Zoom can do). The larger sensor provides greater quality in the pictures during low light scenarios which is night, or the less likely scenario of shooting indoors (with a drone? I mean I guess you could do it but very very few reasons why).
So it depends on who you are and what you want. I bought the Pro as my primary target is movies. If I were just doing aerial photography and didn't care about night, I would save the money and get the zoom.