The Marriott is nicer than Sunscape. The beach is better at the Marriott IMO - I think at one time it was artificially enhanced also, there's a breakwater out there to keep it in place.
Caribbbean Sea Sports is the on-site operator there - Goby DIvers is down the street a mile or so at Veneto. So I don't know why you'd want to do that.
Caribbean Sea Sports I don't know why DreamDive isn't using them since they're on-site at the Hilton also.
At Caribbean Sea sports at Hilton Curacao
The Renaissance has no beach - it's on the cliffs in town. In order to compensate they have a sandy "beach" around their pool. CSS will shuttle you from there to their location in Piscadera Bay anyway for diving. It does have the best casino on the island though.
The other big problem with the Renaissance is it basically adjoins both the Rif Fort shopping complex and the MegaPier. So if cruise ships are in, it's a pretty congested area. Every time we drove down/past there traffic was pretty bad.
Almost all the beaches west of town also have on-site dive operators. So you can both dive and laze on the beach. Porto Mari is really popular for both - weekends parking will be difficult there. It's the double reef dive on Curacao.
There's even a dive off the Marriott. There's the breakwater out there but the actual reef is a farther swim out. CSS guides out there at least one night a week.
I like the Marriott in PIscadera Bay - they have a small casino, a nice upstairs bar, a pool bar and we had a pretty good meal one night at the beachfront restaurant. A fun place walking distance west pas the Hilton is Pirate's Bay - sort of a combo beach bar, music venue, dive shop in one.