Yeah Panama City and David are very safe in my opinion. I've walked at midnight to go get some food. Some girls working the corners but I never felt in danger. I do watch around just in case.. Casco Viejo is the old town, super safe, the president's house is there so guards every corners.
Some areas in the city and around the city are more ghetto, but that's the same in most cities in the world.
Food is overpriced for what it is in my opinion, I've always been disappointed 99% of the time, even on top #1 trip advisor restaurant, it's just not Europe or Canada or refined or anything. Food and cultural event (good dj, music shows, jazz, craft beer event, etc) would be the biggest thing missing. It kinda feel empty and soul less.
The country is quite small but varied: tropical islands, forest/waterfall cooler weather, good highways. Just long drives since everything is linear. David to Panama City is a very long drive, I take the bus so I can sleep instead of doing the drive. Cabs are the way to go around Casco Viejo as there is no parking available and constant traffic jams.
Real estate prices are still affordable for an international hub.
Panamanians are ok to work with, you can joke with them, they're pretty chill.
You can keep your residency by checking in every 2 years.
One point I would disagree is to get citizenship after 5 years, in reality it's changed a lot since Martinelli was in power and is almost impossible nowadays. You'd have to sign up for social security, declare an income, pass a test of knowledge about the country, in spanish, among other things, lawyer fees 3k+. And for what I've been told they re not giving panamanian passport easily anymore, you'll submit and wait for years.
No experience with paid women, not my thing, but you do hear some foreigners who got beat up, scammed or robbed from some bad business with them. Plenty of foreigners, colombian and argentinians in the touristic hubs, no need to pay and get problems afterwards.