We have been to Progresso - you don't really need a taxi, there wasn't much to see in Progresso. We rented a jeep to tour around the area. Some locals told us there is a flamingo roosting area just on the outskirts of town, but, due to a hurricane that came through several weeks before we were there, none had returned, we just saw a big lake. We did drive into Merida, which is a large beautiful city and did some shopping. When we came back to Progresso, we braved one of the local "open" (meaning partially outside, no whole roof and only 2 walls and a burro tied to one of the posts)eateries for some absolutely wonderful mexican food. Don't know what possessed up - we're usually not so brave, but it was great! They people are very friendly, but it is a very poor area. Of course, do keep in mind that the storm had passed through fairly recently, and they still had a long way to go in getting back to normal. They suffered a lot of wind damage and flooding to their home and businesses. This was a couple of years ago, so maybe things are better now. We did enjoy ourselves, and, if you want to hire a taxi, there are plenty available dockside.
Have fun!!