I went to Payar for 2 dives yesterday and here's what I think about Payar.
Let's start with a little bit intro about Payar. Payar is in between Langkawi and Penang. It's a marine park which means it's protected by Malaysia law. Well, marina park is just a name, luckily Payar has a dedicated officer there who really care about the park. Therefore, you get a marine park that really live up to the name.
So why Payar. First, it's the nearest place to Penang where you can see not-so-polluted water. On average the visibility is good enough for you to see the bottom of the sea from the platform. It takes about 2 hours ferry ride from Penang Port to Payar and the crews are very friendly and helpful.
Secondly, fishes, there are a lot of fishes there, and a lot types of fishes too. Although the visibility is not as good as those islands off east coast of peninsular, but when it comes to fishes, Payar beats them all.
Thirdly, it's pretty free and easy, with buffet lunch provided. You just need to bring along your swimming attires or diving equipments. Apart from wet suit, all other diving equipment can be rent from there. For snorkeling, life jacket and mask/snorkel/fins are provided.
Now talk about the weak points. 2 hours journey to Payar means you have to spend 4 hours to and fro, it's not a short trip and definately a killing point for people with seasickness. Bathroom is not enough, only 4 bathroom on the platform and you have to Q for your turn when it's about time to go back (note: shampoo/soap are not allowed there). The foods are not so tasty as well, but since that's the only option I have there, I didn't complain much. :P
For me, it's a nice place to go for a one day trip. But not too often... :P