We booked the Banjaran for the middle weekend of a two week second honeymoon. It was meant to be the highlight, and filled that role perfectly. From the moment we arrived we felt like we were being pampered in a very special place.
Our water villa was absolutely lovely, and it was tempting to stay there, relax, and enjoy the tubs etc. But it was also worth venturing out to enjoy the various pools and caves.
Jeff's Cellar provided an amazing dinner on our arrival night, and we chose the 'In Private' BBQ to be served in our room for the second night, which was amazing (but way too much food for us to finish).
A few reviews mention problems with bugs and monkeys. I managed to pick up a few bug bites on the golf cart ride to the villa, and after that the supplied repellent mostly kept them away. But it's probably a good idea to apply repellent before arrival. The resort isn't particularly bad though - I got a similar batch of bites on an evening walk through Singapore. We were treated to the spectacle of the monkeys sat on our villa roof tearing apart a packaged loofah they'd pinched from a service cart, but that was more amusing than problematic.
A two night stay felt about right. We could have maybe kept ourselves occupied for another day, but there's only so much hot tub one can take.