This is one of those questions that could elicit 50 divergent opinions - most of which would probably be nevertheless valid. It is also a question that you could write a whole book about. I apologize in advance if this gets a little verbose.
I grew up there, about 10 miles west of San Juan, but have been living in the States for the past 30 years. Would I go back when I retire? Like yourself, I'd love to go somewhere warm, where I'd be able to dive or fish daily if I want to, perhaps see the many relatives and friends that I grew up with, and have access to good food (to me PR food is exceptional). So from these respects, PR certainly has a lot going for it.
And it doesn't end there. You mentioned having read a lot of touristy stuff, so you already know that the island offers lots of things to do and see: it has a rich culture and history with many monuments and structures dating back to the days when PR was a Spanish colony. The island boasts one of the most impressive cave systems in this hemisphere; a rainforest on the Northeast, with some gorgeous waterfalls and unique wildlife; and the largest radio-telescope in the world.
The people are very friendly and hospitable - that is not to say that you won't encounter a jerk here and there, but that is bound to happen no matter where. I am of Oriental origin, born in Cuba, and I can't say that there was ever any ill-will towards me because of my race and nationality. Curiosity, definitely.
There are many Americans who live in PR, so I do not feel that there is an anti-American sentiment. Since you are in the Armed Forces, perhaps there is a way that you can tap into the knowledge base of those who used to be stationed in PR at Ramey AFB (more than 30 years ago) and perhaps more recently at Roosevelt Roads naval base, to get their perspectives as well.
Beyond the above discussion, the island is pretty much up to date in terms of modern day amenities: the roads that get you around the island are quite modern - you definitely need a car to get around; you can pretty much buy anything that there is to buy here in the States because many of the chains that exist in the States are already established there; there is cable TV with the same programming that you would get here; and the medical facilities are for the most part up to date - after all, many in the medical field are State-educated anyway.
Is it a clean place? It depends on where you are. Definitely not as clean as Singapore. It also depends on your definition of clean.
Is it a safe place? Also depends on where you are.
If you live in a gated community (and these are sprouting up all over) it will be clean and safe. And living in the more rural areas will certainly be safer and cleaner than in the highly urban areas.
My guess is that the issues of safety and clealiness are ones that you will have to assess yourself when you visit. Just a word of caution, because sometimes things can be a bit misleading: you are apt to see ornamental iron bars at almost every home, especially in the highly urban areas. Nowadays, iron bars are pretty much a necessity for safety reasons, but just to put it in a slightly different perspective: when I first arrived on the island in 1964, houses were already built with ornamental iron bars even though it was very safe back then. It's almost as if iron bars have long been part of the culture, part of the way of life.
So why would I not retire in PR? I think that many of the factors listed above make it a great place to visit or even to stay for a few months, but perhaps not necessarily 24/7 for 365 days a year. First of all, I don't know if living there where it's hot yearround with no discernible change of seasons will be hard to get back to getting used to.
Second, the images that I have from growing up there are of a kinder and gentler time, when the island wasn't as busy and life in the urban areas was not as impersonal, are a thing of the past. I've been back and often dread having to drive around. I suppose there are still places - especially in the more rural areas - where those kinder and gentler times are still present, but I think that they are starting to get harder to come by.
Third, the images of the beautiful beaches that one often sees in the tourist ads more often than not are taken in Culebra, where the waters remain turquoise and clear. The inshore waters of PR itlsef - perhaps due to the outflows from the rivers and the silt that they carry - have long ceased to be crystal clear turquoise and are more greenish......or worse.
I think that for starters, you should visit the island to take a look for yourself, but I would recommend that you expand your visit to cover the entire island. The island is roughly 100 miles long by 35 miles wide. It is not inconceivable to select let's say 4 or 5 hubs for a day or two each (one in the northwest, such as Aguadilla, Rincon or Arecibo, one in the southwest (Cabo Rojo, Boqueron, Lajas or Guanica), one in the northeast (Fajardo or Luquillo), one in the central mountains (Jayuya or Utuado) and perhaps one in the San Juan area, from which you might explore the surrounding areas. Google to find the PR Tourist Board site - it will list a number of Tourist Board sanctioned country inns that are strategically located to allow you to explore all corners of the island.
And last but not least, consider also the possibility of spending a day or two exploring Culebra, which is one of PR's offshore islands to the east, accessible by either plane or ferry. It has the beaches and the tranquility. It may not have the shopping or all of the amenities, but if I had to choose a place to retire in PR, that would be it. But then, that may not be what you're looking for.
Good luck.
