As I looked at the Sundance, it uses electric motors on their slides with seperate electric slide switches. I noticed the Big horn and landmark come with hydraulic slides actuators and use a single master hydraulic pump for all slide operation, thus only one switch is needed. I have to disagree with the previous post indicating hydraulic is better for failure modes. If a hydraulic line blows or a fitting comes loose ( and they do) oil is sprayed everywhere ( big mess) and once the system is drained of it's oil, none of the slides will go in or out until the leak is fixed and the oil replaced. Overall Hydrualic is a smoother system and in theory should be very reliable. That said, give me the electric!!! If and electric motor does goes out, all you have to do is insert the hand crank and crank the affected slide in manually.