We stayed at La Mansion in February 2013 as part of a Costa Rica vacation. We found the staff to be uniformly pleasant to deal with, our room was lovely, and the food was excellent.
This last is quite important, because there is nothing else within walking distance. Prices are quite fair, so this is really a "whew", not an "oops". But it would have been nice to have had some variety. We didn't use the smallish pool (a second one is under construction). be prepared for a lot of walking inside the hotel, because this hotel was several buildings tied together, and we had to walk three separate spiral staircases, and go outdoors (among other things) to reach our room.
room lighting was a bit odd, consisting of inadequate bedside lamps and several tiny bright spotlights in the ceiling - reading a paper book is challenging.
the only real annoyance came when we tried to print boarding passes, because there is no printer at the guest PC. we ended up translating a lot of computerese from Spanish to English in order to print our passes as pdf's, saving them to the guest pc, going into personal email, and sending the pdf's to the desk clerk's personal email, which he retrieved from his pc ten feet away; he then printed for us. sorry, gang, please buy a $100 printer and save your guests' sanity.