Spent 3 weeks in San juan Del Sur, Nicaragua last summer. Unreal. Head high at least some point everyday. Offshores just about everyday, uncrowded, untouched waves. Prepare ur self for an adventure. Nicaragua is the second poorest counrty in the western hemisphere. I stayed at an orphange and worked as a surf missionary, pretty amazing experience going bakc this summer then up to el salvador.
surfed bocas del toro in panama for a week. epic my friend! The one week i spent on those islands over weighted the whole month and a half long trip to costa. Panama is way cheep and has a super mellow vibe. Great range of breaks too!
Spent many months in Panama. There are great waves from Panama City to David on the Pacific and the Caribbean side is full of islands and world class breaks. It is not as cheap as it once was and there is a huge push to retire Americans there but overall still a great place with friendly people. I was last there in the winter of 06/07 and my first trip was in the mid 90's.
season matters in these places... For the Pacific breaks the fall/summer/spring season is ideal, since these areas pick up S/SW swells. Caribbean side of Panama will break all year, but winter is most consistent and generally bigger.
I've been to both, although not on a surf trip. I biked through central america a few years ago. I can't comment on the surfing per se, although I spent time in both bocas and san juan del sur. I thought that Nica was overall much cooler. The country is very poor and undeveloped, meaning not that many tourists. San Juan del Sur is a fun little town. Some nice bars and right on the beach. I stayed in a VERY cheap hotel there- I think it was like $6 American a night for me and my buddy. Bocas, on the other hand, is very developed (at least on the bigger islands), harder to get to, and has less personality (in my opinion). Waves were more fickle when I when I was there, but apparently they were great right before I showed up (..."you should have been here yesterday!"). A lot of Europeans and Americans. There were some cool bars though, including one that you had to take a water taxi too, and a fun hostel scene. Bocas has a strong military presence, which was weird. You will get a fine if you walk around with your shirt off, and not sure if its your thing but drug laws are super strict in Panama.
Assuming waves will be good at both places, I'd recommend Nicaragua.