I've gone to Aruba and stayed at the Renaissance both times. The food in Aruba definitely seemed better than other Caribbean islands I've visited. The Renaissance hotel was older but had a couple unique advantages. Primarily, the Renaissance had a beach front building/lot (family oriented) and a marina building/lot (couple oriented). A boat ran between both properties and a private island owned by the hotel. In the case of the marina, the boat picks you up in the lobby. The island includes food, drinks, a couples massage hut, etc. It sounds like you've got lodging covered, but if you're going with some aspiration to "relax in peace", this island was a nice option (since only Renaissance guests with a room key can use it).
Keep in mind that restaurants change and that I was last in Aruba ~3+ years ago. We also didn't make an effort to pursue some of the nicer dining establishments as we spent most of our time here outside and active.
A snorkel trip is fun if you can manange a booking that isn't crowded. I also enjoyed a sea kayak trip (in a small group) and an off road tour of the island's backside. In the case of the off road tour, it may go down as my only chance to have driven a Land Rover Defender
Some comments on restaurants that I can remember. As I said above, we didn't really pursue fine dining but stumbled into these places. Many are a few miles from the Marriott Surf Club.
Brazillian churrascaria restaurant. Better than most restaurants of this type. If you've never had this style of dining, it's worth going once. I remembered the meat quality being better than other churrascarias I've attended.
This was excellent and themed like Azull above (although we chose not to go to both so I can't comment on Azull). Seafood was fresh and prepared well but the attraction here is obviously dining on the beach in the early evening.
Nice little place. It was affordable when we visited. Located near the Renaissance hotel (closer to the airport than your Marriott) and a few blocks back from the water. We shared a huge (mostly fried) seafood platter for just under $30 and drank some Heinekens.
This is a casual restaurant a block or two from the Renaissance hotel. I was pleasantly surprised at the quality of food. Based on menu content, I expected an Aruban "Applebee's" but everything I had was on the better side of average. I went against common sense and ordered a 10oz Argentenian fillet (including sides) selling for under $20 but it was surprisingly very good.
We did a snorkel trip that was catered by a supposedly good French Restaurant (Le Dome, I think) but I was unimpressed by what was brought aboard our boat. To be fair, this isn't my type of food and boat catering limitations aren't going to give the best representation of a restaurant's capability. Nevertheless, I can't recommend it.
The best advice I can give you is to read reviews in order to tailor activities and restaurants to your tastes. I like tripadvisor.com for this purpose.
All in all, a nice and unique caribbean island. Fantastic weather.