Same experience as Aubrey here regarding laughable NCL comp offers.
I'm typically a table games player so I can't speak to the slot payouts or anything like that. That being said, I've always had great experiences with NCL table games/dealers/casino staff/etc.
I wasn't a huge fan of my first RCL trip (I have my first Carnival in October and second Celebrity booked for 2023), but one major plus of RCL's "Club Royale" is that they are extremely transparent in terms of points earning, benefits, and comp offers. They have a separate webpage dedicated entirely to casino offers where you can see all available comp offers and discounts after you input your information. They are also extremely consistent about sending comp offers via email and hard mail: something NCL never does.
Unfortunately, NCL's comps are hot garbage right now compared to other lines so for now I'm cruising with everyone else when I save a thousand+ per trip before even boarding for comparable cabins/ships/itineraries