Palmetto to me is a wonderful turf if it is maintained very well. Palmetto has a horrible time with fungus. I mean horrible. It can wipe your whole yard out in a matter of days. During really raining/humid conditions you might see yourself spraying once a week to keep the grass healthy.

The first signs are yellowing of the turf, and then brown/necrosis of the turf. Be very vigilant in checking your turf every week. You should see some relief during the winter, and spring, but again it will pick back up in the summer.

If you choose to re-sod with Palmetto, I would nuke the soil with a fumigant. This will remove any pathogens, or bugs currently in the yard. Send off a soil sample and correct any problems before sodding. When watering in new sod, water in the mornings that way the sod can dry out before night time when it will be most humid. And monitor your sod. Also contacting your sod supplier and ask them what they use to treat the fungus, and use that. There is no sod producer growing Palmetto in Florida that does not have to deal with this fungus.

If that sounds to much for you I would try a different cultivar. Floratam, or Bitterblue are nice. Also Seville is a nice one. I would still fumigate, and soil sample before you sod.