We did 2 nights trip to Ko Phanang and decided to stay in Saritankang. That was right decision. Very nice hotel, great staff, nice private beach (sea was not swimmable because it was so shallow, but it didnt bother us) and SUPER clean room.
Also the location was great for us, lots of restaurants, bars etc. at a reasonable distance. If dont have a motorbike or dont want to walk, there is a free shutte. Overall, nothing bad to say.