Have cruised both and found it to be like comparing a Ford and a Chevy. Both get you there but the loyalists to one or the other SWEAR theirs is better. We are loyal to "RCI" for 2 reasons; #1 is the Radiance class ships (love the size/layout and open spaces) and #2 is the repeat cruiser program. NOT because it might be better than "Princess" but just because we wanted to get to the top level with at least one cruise line. We have been "Diamond" level for a bit and now it also benefits us since we are "Elite" level with "Celebrity" since "RCI" purchased them.
Wife doesn't care which line we cruise with and Mom used to prefer "Princess" when she and I cruised but now she also prefers the Radiance class ships to "Princess."
Hope I didn't muddy the water, Robbie