Gotta side with @NE John here. His observations about cabin size matches the differences between HAL's Vistas and PInnacles. Cabins on Koningsdam are smaller than the same category on Westy, Zuidy and the other Vistas.
I did not get a feeling of spaciousness on Koningsdam. Yes, there's an atrium. But its wire cage design makes it closed in, not spacious. Yes, the MDR is large and very open in the middle--all of which contributes to dreadfully noisy acoustics. Yes, there's more space by the midship pool, thanks to the double deck. In fact, the only part of K'dam that I liked was the pool area and movies at night. And don't get me started on the too-small "world stage" theater or the overcrowded spaces in the "music walk."
I am booked on QA, and my itinerary is mostly sea days. I'm willing to give her a try, trusting Cunard to take the basic Pinnacle design and (except for the Prom deck, which can't be changed) make it into a ship I can be happy on. And just in case it does feel crowded, I booked PG, hoping to have quiet time on the grills terrace. Hedging my bets.