The Casa Jungla Hostel is a beautiful place, with a lush forest, and nice areas (and hammocks) to hang out in. The hosts are nice, although their English is limited, the breakfast is good, and there's lots of coffee. It is in a good location, a bit south of the main stretch of Jaco, so it is quieter, but the beach is nearby and nice. However, the rooms (at least the one I was in) are small, dark and not really well furnished - although for the price, I guess that's the best I could expect.