My wife and I are from Costa Rica. We have been living in Switzerland for almost 3 years, so maybe I can provide to you my point of view of living/retiring in Costa Rica:
PROS:
- Everything is cheaper compared to CH. So I bet that even if you get taxed by the CH goverment, the remaining money will allow you to live quite well.
- In general people are friendlier and happier than most Swiss people I have come across.
- Quite a lot of the people speak basic or good English. So if learning Spanish is not your #1 priority, I believe that you should be ok with English (most of the times).
- Awesome beaches, national parks and even active volcanos (not dangerous).
- Well connected to/from the US wth daily flights from AA, Delta, Continental,...U and also there is a daily flight to/from Madrid, Spain.
- More and more US retired couples are relocating to Costa Rica, and they live in the Pacific Coast...so for this reason there are many well-equipped condos and apartments: (swimming pool, completely furnished, 24 hour security,...).
- The weather is really nice. There are only 2 seasons: rainny and sunny. The inner section of the country tends to be colder, and over there the minimum temperature recorded this year was around 14 degrees (C).
- People like to party and have fun, so you can be sure that there plenty of places open until late, even on Sundays! The same goes for the supermarkets, some of them are open until 23:00.
CONS:
- Eventhough the public transport network/system covers almost all of the country, the roads are in really bad condition. Lots and lots of holes and even craters that force drivers to zig-zag...this is also a main reason for accidents.
- People tend to drive dangerously. A lot of people are involved in accidents because of drunk drivers.
- The capital is an unsafe place to be. Sadly since 25-30 years ago, people have had to put steel bars around their homes in order to avoid being robbed. We say that "families live in jails, while the criminals roam free in the streets"

- Again, in the capital, some people try to take advantage of the slightest slip to steal something from you...as an example: early this week there were 2 of the surviving Chilenian miners telling their story to some students at a University, and in the mean time someone stole their passports and their laptop!!!
In general, I believe that Costa Rica is a great place to retire if you intend to live away from the capital...so this means to find a nice condo on the coast. My wife and I also plan to return to Costa Rica once we retire.
As with any other country, there are plenty of pros and cons, so maybe the best advice I can give you is to do a small research trip to Costa Rica before taking your final decision.
Oh and one more thing: be confident that every year you can feel 2 or 3 mid-tremors (nothing to worry about) and every now and then (maybe every 12-20 years) there might be an earthquake, but the construction quality of new buildings/homes is very good and resistant.
I hope this helps a bit...