After playing around with the equipment, I think it’s just that the rental camera had a much brighter display, which in the end sucks for me.
Here’s a new question: I’ve tried using FCP’s color correction to have the image look as close to what the camera display has, but it tends to wash everything out as I lighten the shot. Does anyone know of a good program that would be better at emulating the desired look similar to the pictured camera display?