We went to the Westin for our site visit and it was great! I don't think you necessarily have to visit the places, just do research and ask brides that got married at the places you are considering! Anywhere you chose will be great regardless! Here's my site so you can check it out!
http://allaboutjingnjeff.weebly.com/
Christine (a member on this forum) did a couple of site visits and got married @ the Marriot. And shes really helpful! Here's her site:
http://www.ourarubawedding.com/
Hope this helps!