Renaissance is very nice, I was there in November. Great service, breakfast is amazing, pool is spectacular by the beach. Got upgraded from the standard room to the two bedroom private pool villa, right next to the pool and beach!
Also stayed at the Anantara Vacation Club (different to the Anantara Villas Mai Khao, not as great). If you can bargain a good rate direct, it's worth it. I paid £180/nt incl taxes for a 2 bedroom pool villa for 4 people. You have to listen to a 2 hour sales pitch for the timeshare though.
Between the Ren and the AVC, definitely the Ren is better. But likely more expensive too.