Just returned from a two week trip to Nicaragua. Visited Little Corn Island and San Juan del Sur with a night in Managua in between.
Didn't want to rent a vehicle for the SJdS leg, so poked around for a driver service. We used Nicaragua Escapade (online at http://nicaraguaescapade.weebly.com/index.html) and couldn't have been more pleased.
Rodolfo Ortega was excellent in communicating via email during the planning stages.
Our driver, Julio, was extremely prompt for our pickup in Managua and our pickup for the return in SJdS. He spoke good English and was very friendly and interested in talking about his country (as well as professional baseball in the USA - which was great, as I'm a huge baseball fan).
Our lodging in SJdS was a bit out of the way with no signs, so there was a tiny delay in locating it. However, we found it and Rodolfo Ortega called his driver and put me on the line to apologize for the delay. It really was not an issue, but the gesture was appreciated.
For an efficient and economic way to get between Managua and San Juan del Sur, I have no reservations recommending Nicaragua Escapade.