I stayed at Luna Llena with my girlfriend for 3 nights in mid August 2012. Of all the places we stayed at in Costa Rica, this had by far the nicest layout. Nestled in the hillside, it really feels like you're part of the jungle, especially when the monkies come running across the roof. Like others have said, its nice to be away from the loud party places downtown, but still be only a 5 minute walk to them and the beach (I hope you don't mind walking uphill). The rooms were nice, we stayed in the dorm one night and then room number 9 the other 2 nights. Cleanliness was great in the rooms, the bathrooms, and the kitchen. Security was also great, we stupidly left our wallets out on the nightstand in the room and even a bunch of cash right next to them but they were untouched when we came back (and it was obvious that the rooms had been cleaned). We did accidentally leave shampoo in the shower room and a half bottle of rum in the lounge area overnight and they were gone in the morning, but we kind of expected that. Milly, the owner, is very sweet and accomodating. Overall, if you're in Montezuma, go here. cheap, chill, and fun.
The best parts: The orange and white cat, the architecture, the fact that it is not a crazy party place, and Julio, the Friday night security gaurd!
The drawbacks: There are ants (big red ones) in room #9 but they never bothered us (there is a mosquito net over the bed for extra security), the fact that the lounge area closes at 10pm.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.