A few thoughts...
Having visited both the Atlantic and Gulf coasts of Florida many times, I have consistently found the Gulf to be better for swimming than the Atlantic. In fact, I think that the Gulf is a great place to swim.
Here are a few reasons:
1) It's usually calm. The Gulf has smaller waves and is generally quite calm.
2) In most places, the Gulf has a gentle slope out into the water. Even small children can often go a long way out and still touch the bottom. In contrast, the Atlantic has steep drop offs in many areas.
3) Very little undertow in most places. Most Gulf beaches do not have a problem with undertow.
I read the post in another thread that you are referring to which listed all of the bad things about swimming in the Gulf. Quite frankly, I was a bit surprised by the negative tone. It was written by a Florida resident who obviously doesn't work for the Chamber of Commerce or Tourism Board.
More seriously, there are potential hazards with swimming in any open water area like the ocean or gulf or a bay. Those mentioned in the other thread certainly aren't unique to the Gulf of Mexico. In fact, many of them are worse in the Atlantic...not better.
For example, the Singer Island/Palm Beach Shores area that you are considering is a very popular location on the Atlantic side of Florida. It's home of Marriott's Ocean Pointe and the new Marriott Oceana Palms. But it has some serious issues when it comes to swimming. Have you read about all of the shark sightings there? It has some of the most sharks of any beach in the whole USA. Also, there is a steep drop from the beach into the ocean. And there can be rogue waves. A year or two ago, an elderly woman who was walking along the beach with friends...not even in the water...was swept out to sea and never found.
Based on all of this, you might want to cross the Atlantic side off your list. Or not. I'm just trying to give some perspective as I don't believe the Gulf beaches to be a high risk area compared to others. Indeed, I think that the Gulf side of Florida is safer than the Atlantic.
Steve