This is a fantastic island near Krabi and it is actually very cheap compared to most other islands in Thailand. It also tends to be much less touristy than other parts of the country. It can actually be quite difficult to find a place to stay there in low season since most of the operations shut down during this time (May to October.)
I'm gonna try a different approach and do a pro's and con's this time around. Perhaps that will be more helpful.
PROS
the beaches tend to be quite empty because the island has not been overdeveloped. There is only one road and it doesn't even go all the way through the island. There are a few motorbikes kicking about but for the most part there is no road noise at all.
Many of the bungalow operations you will simply arrive by boat right up to reception. It's pretty cool to check in like this
Lots of open space: No one has tried to maximize their square footage - so to speak. Also, most of the bungalows have tried to disturb as little nature as possible in their building (lots of shade.)
There isn't a lot of boat traffic to ruin the ambiance because since there are normally very few people on the island at all, there isn't a lot of group tours coming and going. This is also not a destination for day-trippers.
There is a wide variety of accommodation from fan bungalows for $10 a night all the way up to multiple bedroom villas with private swimming pool for i-don't-know-how-much. It's a lot, I'm sure.
very safe and fun environment for groups and families as each of the bungalows seem to have vollylball nets, lots of beach games, and plenty of hammocks
I've been here many times and I have never seen it crowded
CONS:
It can be a bit of a pain to get to especially if the ferry to Koh Lanta (it stops halfway) isn't running.
Not a wide variety of dining options. The bungalows are pretty spaced out (which is good in many ways) but you are likely going to be subjected to the culinary options of whatever they have where you are staying.
some of the bungalow operations have rocky coastlines and they are likely to conceal this fact in their advertising.
Most bungalow operations are closed half of the year
There are never any waves (maybe this is a pro for you but it isn't for me.)
Be sure to check to see if your bungalow choice offers assistance in getting you to the place because it can be a bit of a chore to find your bungalow if they don't already know exactly how you are arriving. As I mentioned before, there are not many roads here and you could be in for a long, sandy walk with a suitcase if you don't plan ahead.
I hope it's helpful. As always I welcome your comments.