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I think your observations and those of Berlitz are spot on .... RCCL are for the mass market and the family withy plenty of organised activity, ranging from rock climbing to party games on deck ... as such they are far more holiday campish than Celebrity and their food, although perfectly palatable is far more plain fare. They are rather like P&0 in that regard and I believe Celebrity and Cunard are classier and quieter.
Suggest you read the reviews over on cruise critic to get a varied honest opinion by a variety of cruisers. RCI is a 4* line and Celebrity is 5* - so of course there is going to be a difference. I have heard that the live music by the pool is going to be stopped [thank goodness], and yes there are a few announcements - but in no way is it 'noisy' or a party boat like Carnival are.