I can't speak for the Celebrity Retreat as I've never sailed in it. I can, however, speak for the Haven on NCL. Our last cruise was in March out of New Orleans on Breakaway. We had a Haven Spa Suite that was outside the Haven proper. So, we had to go one deck up for meals if we wanted to go to the Haven Restaurant or Lounge. Didn't mind that at all! I didn't find the service at the Haven Restaurant slow, as some have said. The private pool area was nice with a pool and two hot-tubs. There were two children (only two) that were running amok in the pool area. Their parents did nothing to control them. We were sitting in one of the hot tubs, the one that was marked "Adults Only", when the little darlings tried to dive in. Both my wife and myself told them that this hot tub was for adults. The little boy, who I think was doing the talking for the duo said "We're in the Haven. We can go anywhere we want!" I moved over next to the child and said, "If you come in here I'll have to break your little arm". (I saw Steve McQueen use that line on a kid and it worked very well!) It worked just as well for me! The children always gave me a wide berth for the rest of the cruise! I'm getting off-topic here. My next cruise is on Silhouette in an Aqua Class cabin. I hope to get upgraded, but if we don't, no biggie! My Haven cruise was at 65% capacity. When we speak of the good old days of cruising, this is what we're going to refer to. Like I said, I can't speak for Celebrity Retreat (yet), but I would have a very hard time sailing on NCL and not be in the Haven!
Elvis