Smaller Hotels On Phi Phi Or Koh Samui?

[Tedhead]

Here's the story. My nephew is travelling to Thailand for the first time at the end of this month (26th). He likes the look of Phi Phi (yes, he saw it on that <deleted> movie) and wants somewhere to stay that's 'clean and safe'. That is, hot water and somewhere to lock up his valuables. His preference is for a small hotel, not too pricey.

I had a look at some of the hut resorts on Phi Phi and they seem ( a ) not that cheap and ( b ) have some terrible reviews on the likes of TripAdvisor. Does anyone have any suggestions for the type of place he's looking for? To whit, decent accomm, good value and you feel comfortable.

If Phi Phi ends up being too expensive, the alternative would be Koh Samui, on the quieter parts of the south coast. It does seem a lot cheaper, although I'm wondering why.

Thanks for the help in advance.