If you've been to a Gold Coast, Australia theme park you'll know how painfully expensive a day there can be. In comparison the Genting Theme Park is excellent value. It's no Disneyland, and probably is a bit dated, but my kids had a great time there. The girls thought that my screaming all the way up and down on the Space Shot was a laugh (don't do it - it's terrifying), while once was enough for me on the Pirate Ship (but once was not enough for the kids). We also enjoyed some of the gentler rides for the little kids, and "unfortunately" missed the roller coasters as it was closing time. Like all these sort of places the food and beverages is expensive (at least by Malaysian standards but not by NZ standards), but at least the food is reasonable. When we were there, between the school holidays and the Chinese New Year, they were doing maintenance on the cable car so we unfortunately missed that. My kids already want us to go back on our next trip to Malaysia so there must have been something right with it.
One warning - do take a sweatshirt, jacket or jersey. Coming from New Zealand I couldn't believe I would be cold in Malaysia - but there was a cool breeze. Also don't forget your sunblock - it was the only time I got sunburnt in Malaysia because with it being cool I thought I would be okay. We took a taxi up (pretty good value and great service) which we booked next to the Genting counter at KL Sentral station. We took the bus back - finding the right place to go was a bit of a struggle and led to a little domestic difficulty.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC