Krabi and Koh Lanta

[pilot]

Hi, I had a quick search through the other threads but haven't been able to find one that really answers my questions. I've got 4 nights coming up in or around Krabi and I need some advice on where to stay and what to do there as I've never been there before.

Two of the Hotels I can stay at are on Koh Lanta (Langham and Pimalia Resort) and the other two are in Krabi (Sofitel and Nakamanda Resort). Has anyone stayed at any of these? And is it worth the boat trip to Koh Lanta for just 4 nights?

I'd also appreciate finding out about any must-see places or things to do (incl food!).

Cheers,