It's all pretty sweet everywhere I've been so far, I just don't really prefer the beach for work/heat/distraction reasons, but I do visit whenever I can take a day or two off. There isn't really anywhere I wouldn't recommend outside of the Limon/Moin port area (I don't know any good port towns in the caribe, to be honest, too much drug traffic drama)... just keep in mind the further from the city you stray the further from good internet you're getting with the exception of certain places... Puerto Viejo, it's pretty far off for example but they're well connected enough