Ride quality is completely subjective and honestly impossible to define. For me, the Expedition is the nicest, smoothest, quietest vehicle that I have ever owned and I have been completely blown away with how well it handle and rides both on and off road. I am also utterly shocked by how quiet it is, both on and off road. Its really hard to compare a CX5 with an Expedition...sure they are SUV's but that's like comparing a banana to an apple. Sure they are both fruit but...nothing a like. If the CX5 had a suspension setup to handle a 9000+lb trailer weight then we could compare ride quality. They just aren't even the same type of SUV, I think a CX5 would fit in the back of my MAX?
Anyway, I do think the CCD suspension rides a bit better but it is probably tough to get a better ride out of the expedition without some sort of adjustable suspension, air ride, adjustable shocks, etc. I have the base xlt so no fancy suspension for me. I honestly couldn't be happier.
I do notice a slight amount of bounce in the rear when the expedition is empty. Even just getting my 5 kids in the car and full tank of gas seems to calm that down. If the trailer is hooked up and we have 500+ tongue weight on it, everything is great.
I moved to the Expedition from a 2010 Jeep commander limited, that was 60k when it was new so definitely in the more "luxury" range at its time and the ride in the jeep (on and offroad) is trash compared to the expedition. Anyway, I can totally see how someone coming from a luxury car (acura, lexus, etc) could drive an expedition and feel the ride quality isn't the best but I would be hard pressed to say it is worse than ANY other full-size suv that can tow 9000+lbs.
Lack of the air suspension did keep me from buying a higher model expedition.