Best place to live in

Wich of these would be the best place to live in?

Costa Rica

Cancun

Panama

With great schools, food, security, weather?????

I would suggest you look into Belize.

It depends on what you are looking for.
Costa Rica is still a nature lover's dream but it is getting expensive and has no incentives for expats moving there.
Belize is small, undepopulated, in my opinion  boring in the long run and has only pseudo incentives for expats: a program which forces you to spend a too high amount of dolars (comparing with what a country has to offer and what other counries let you go away with).

Cancun is artificial as it was built for tourists, but if you like the crowds and a dose of multiculturality with some incentives for expats  and decent cost of living it is a good bet.

Panama is a bit of everything: an authentic local culture, lots of incentives for expats, seaside and jungles, and a big metropolis, with a  cultural scene to match. You might like it.

And all except Belize are Spanish speaking, which you might prefer.