I've stayed at both, and I much prefer Port Orleans Riverside. The food court is worlds better than the one at CBR. Also POR has 3 less bus stops than CBR. To me, it made a big difference when going to the parks and coming back at night. At CBR it felt like you were on the bus forever before getting anywhere.
CBR is pretty, but it is huge. We were in a non preferred room, and I wouldn't do that again. It made my refillable mug all but useless. At night, after a long day in the parks, I didn't want to have to hike to the food court, refill my mug, and then hike back. Half of my pop would be gone by the time I got back to my room anyway! I ended up buying pop from the machine by my building.
Picking between the 2 POR gets my vote, no question.