To supplement what you find here, you may want to post your question at
www.cancunandrivieramaya.com at their 'vacation here' forum. A search there may also yield a few trip reports.
The FACB and the Ritz are the 2 nicest hotels there. The JW Marriott is fairly new and quite nice...the CasaMagna is a little older.
Maybe you could come back and post what you find here to benefit the rest of us?
Good Luck