I will probably say that this is what I felt (hotel within a hotel). The adult-only section is definitely designed so that you can spend most of your stay there. I've seen kids come to the Nirvana pool but that's not allowed for sure (there are signs that clearly say that this section is for Nirvana residents only). The staff working at the Nirvana section are more proactive and they will do anything to make sure that you're happy. Most staff knew my name and room number. In the lobby, the receptionist knew my Marriott status simply by looking at the name on my passport meaning that they were expecting me so she memorized my name and status which is unusual. Other pool areas are great too and they do a lot of activities over there.

Unfortunately, I can't speak for the regular rooms but from what I was told, everything was fully renovated. I would definitely save up my points and book the Le Meridien.