Cartagena

I was there for one week and stayed in Bocagrande, about a 10 minute taxi ride from the Walled City. Pros of Cartagena: Inexpensive locale, reliable and fast internet, good weather (if you like it hot), not terribly crowded (aside from Walled City), beauty/history/nightlife of Walled City. Cons: Local beaches are average at best and riddled with vendors who accost visitors non-stop, street vendors are less pushy but everywhere, fluency in Spanish is very helpful (not really a con, just is), Walled City is loaded with tourists and priced accordingly. Cartagena struck me as a one-trick pony like a Las Vegas. Some people love Vegas because of the weather and the entertainment. Cartagena has the weather and the Walled City. Unfortunately even though its a coastal city, it's tough to enjoy the beach.

The beaches are not good. You'll have to go to the islands or natural park if you want a nice beach. Unless you're looking fo a Miami remake, don't stay in the area with all the newer high-rises. The walled city is cute, but it's not worth staying there. Within a day you've seen it all and it's relatively expensive. Everyone is a tourist and it's super hot because there's no breeze with the walls. I recommend staying in a residential area south of the high-rises. It's a safe and charming place with friendly locals who are always out on their porches. Everyone says hello to you here. More culture, more affordable, laid-back, but no co-working.