I had both the Frommer's Costa Rica travel guide and the Lonely Planet Costa Rica travel guide, and in my opinion, the Frommer's guide was better. I felt that the writing style in Frommer's guide was conversational and easy to read, while the Lonely Planet guide was a little more like a textbook. One thing I did like about Lonely Planet was that it gave more background and historical information on the towns and attractions, but the Frommer's guide gave more recommendations for accomodations, dining, and things to do, which was more important to me.