You seem like a thoughtful guy - there are many beachfront across the street places to stay in Cha'am for a vacation. I have not been in years but used to enjoy Methavali which I believe has a refurbished newer wing, which would account for some of the mixed reviews I have seen... as the olld wing rates poorly - but nice pool, nice location.
As for the rest of it, shop around - my opinion being the further south you go, the more beautiful but the less you feel like you are in Thailand... for worse, not better. I have enjoyed vacations there but not for living there.