We have polished concrete floors in our house in Pátzcuaro and after 5 years we have a few very minor cracks. The floors are divided by bands of small beach rocks laid in white cement, and there is a shiny coating on everything. If you're bothered by tiny cracks then this floor is probably not for you. Even if you put tile on top there will be the same little cracks underneath.
We also have in-floor heat, and if you decide to do that, please be aware that no single zone should be longer than 300 feet of tubing. Our system had only 3 zones, all of which are much too long, and as a result we have spent a lot of time and money getting it to work even marginally. My husband has just about torn out what's left of his hair working on this. It works now, but I don't think we can afford to run it. Fortunately we need it less than we would have in Colorado, but we have become very familiar with the gas truck driver. Basically it's 1500 pesos every 2 weeks.
Now if you can get it installed properly, I can vouch for the comfortable heat it produces. There's really nothing like it.
See if you can find a contractor who can properly install the floor and the radiant system. Once you have the concrete floor you don't have to do another thing to it, just sweep and mop it.
Nancy in Pátzcuaro