I'm skeptical about Cuba right now. Heard recent disturbing stories of tourists being jailed for suspicion of sex tourism (used to be just the chicas got in trouble). Cuba is short of foreign exchange right now...so perhaps some extortion happening. Who knows.
Costa Rica is still the safest in my opinion...as far as just doing it, not worrying about police, etc. and being able to pick and choose openly. Last time I was there went to a hotel...chicas came into the bar, pick one, negotiate price, go to room, next... All legal, safe, and technically I would not have needed to leave the hotel. But I do...I walk, I go other places, I study Spanish, waste a bit of time in casinos, go to massage places. Really unlike almost anywhere else in Central/South America.
Colombia is great...but doesn't have the point and shoot convenience. But still...go to casas...pick one out of the line up, pay or agree on time...do it. Done. Or many other alternatives. But almost none as simple as the Costa Rica options.