Hi. Have been to Costa Rica and spent time in other countries in Central America but have not been to Belize or Panama. Hard to compare an island to an entire country. Of course speaking Spanish would be necessary or at least very helpful with retirement in either Panama or Costa Rica. Belize and STX are English speaking and not sure if you could work or work easily (if desired) in either Costa Rica or Panama. STX has some medical care but if is not extensive and would need to go to Miami or other mainland cities for things that are not routine or requiring specialist that are not on island. We have friends that are living there presently and are in their 50's and 60's with some medical issues and so far are getting their needs met. I would recommend a visit or longer stay if you can arrange that prior to moving anywhere to see if it for you. There are likely business opportunities especially if your business can hire local people to help the economy. As for beaches, there is a very nice variety, but have not been to Anguilla or St. Marten to compare. Hope this helps you out!