We have been spending a few weeks in Cabo for the last 13 years, and always enjoy trying new restaurants. We were very impressed with our 1st visit to Casiano's a few years back, and have now returned with family and friends, 4 times. Our most recent visit was this past March, 2013.
The service is always impeccable, and we have really enjoyed the "spontaneous cuisine". We are always amazed how easily they can adapt the courses, even when someone has a food allergy. Our son is a European trained chef, and found the meal to be beautifully presented, thought the food was excellent, and wine pairings were very well matched. On our most recent trip, the couple we dined with own a restaurant in our hometown, and he is a chef as well. That particular meal ended with a short visit to the kitchen to meet the chef, and see the workspace.
Casiano's is a "quiet space", we have only been there once, when there were more than a handful of diners present. They do not have a bar scene, and it is located in a residential area which is very nice, but you will not find incredible ocean views here, if that is what you are looking for. We enjoy their outdoor patio, but have also dined indoors, which is more intimate The staff is extremely knowledgeable, and I think part of the dining experience is based on how much involvement you have with them. We always have them explain the ingredients, and how the dish was prepared, especially, if there is a particular item we are not familiar with.
We feel it has been a great addition to the food scene in San Jose del Cabo, and look very much forward to returning next year. If you are a "foodie", it is definitely worth a visit!
(Note: This restaurant does not have menus. Chef prepares what is local and in season, that is why they call it "spontaneous cuisine.")