My wife and I visited eight beaches in seven days on St. Martin. The reason we went to eight instead of seven was our visit to Baie Rouge. When we got to the parking lot for Baie Rouge, we looked for a place to change into bathing suits. The only place was an outhouse that was more than a bit grungy. I am not picky, but this wasn't to our liking. Also, if you are going to stay at a beach for a day, it is good to have a reasonable restroom to visit.
We did look around the beach before we left. You can read the rest of the reviews for Baie Rouge. The beach is truly beautiful. It is small, but that can be a plus. At the time we were there, there was renovation to the places to eat, and as others pointed out, the chairs and umbrellas being rented were the worst on the island.
A really interesting point about Baie Rouge is that it is in the island's richest neighborhood, Terres Basses, which has houses, or rather estates costing in the many tens of millions. However, they are all gated, and you can't see them from the streets. However, by taking a short walk on the beach, you can see a few of them. This is the unique thing about the beach at Baie Rouge.
There are many things that need fixing on St. Martin. The streets and roads need street signs so you can tell where you are on the map. The massive pot holes are everywhere and they need to be filled. The island's vast population of poor folks offer a way to get this done rather inexpensively. Signs need to be erected on the exits from each of the many roundabouts to let you know where each is leading to. And the facilities on Baie Rouge need to be brought up to minimal standards. To find that Baie Rouge, which exists in the richest neighborhood on St. Martin, has such poor facilities was a real surprise. However, the fact that it is beautiful, and small, and not so crowded, still render it worth visiting. Just wear your bathing suit to the beach, or be willing to change into it in your car.
Please note that this review is not a complaint. It is a comment. We thoroughly enjoyed our week on the island, and we are looking forward to returning. Putting up with some easily fixable negative aspects of the island is not a reason to stay away.
By the way, you need a rental car if you really want to see the island in a week. But as others have pointed out, some of the rental car agencies are problematic. This has been written about quite often. They point out small scratches or other things which you didn't think were big enough to note on when you did your inspection of the car. When this happens, there is really no way out. You need to get to the airport, so you just pay it, and you learn a lesson. Luckily, there is a way to avoid this. Check into the rental agencies ahead of time. We rented from Hertz. There were no problems with our rental at Hertz. I figure that I may have paid a bit more for a relatively nice car from a reputable organization than by renting a "Rent A Wreck" from a LOLO, but it was money well spent.