Have stayed at both the places, the RIU and Secrets Wild Orchid.In terms of the beach I will stay they more or less are at par but still Secrets is one notch up.Not much difference.
Secrets is definitely better than the RIU beaches because of the below reasons:
At RIU you have to wear bracelets and make reservations for the speciality restaurants none of which you have to do at Secrets.
RIU has an option to eat buffet for dinner which was not available at Secrets for dinner.Secrets has crazy waiting for dinner and can be frustrating.
The breakfast at both place is great (its a buffet style)
At Secrets in the evening there is usually an open air show, which takes place along side the most beautiful view of the mountains and post that they usually around 11pm open the Desire's club, which is air conditioned and has nice couches for seating. Club is top notch.Must visit