In reply to JAMES K:
I was out there in March / April 2018. Yes there is definitely some polish, especially on the easier routes, and I also thought the stuff we were on was relatively hard for the grade (climbing upto 7a).
We stayed at Tonsai first (Tonsai Bay Resort) which was laid back and generally populated by climbers. Places further back from the beach are cheaper but by UK standards its all cheap and the resort was pretty nice. Moved around to Railay after afew days (can walk or take a long boat) which was more tourist centred and busier. There are some great crags at both locations and suspect if you seek the ones out away from the beach polish becomes less of an issue. At those grades you should do 'Where Eagles Don't Dare' at Eagle crag. We took kayaks around to the beach. Superb!
Also did afew days on Koh Phi Phi. Climbing was pretty decent, although not extensive, but the island is super busy and over crowded.
My overall thought was there are probably better climbing areas around the world given the distance involved from the UK, but the landscape is stunning. Taking the long boat around to Tonsai for the first time I'd challenge anyone not to be blown away.
Have a good trip if you go. Don't drink fruit milkshakes with local ice!!