Hi Memo
My son was with my sister till 18 months and then he went to a small daycare. They have 6 kids in his class. My child was also VERY spoilt when he went. In fact, when he started he would not go down to sleep without his teacher laying down next to him (which she then did for the first week or so). He cried for about a week and then was fine. If I ask him now does he want to stay at home or go to school, he says school
He has got sick a few times (colds etc) but not overly so. He is a very social child though.
For me, the key thing in both situations would be:
If you get nanny, go with your gut. Do the references and pop by on odd occasions if possible, especially in the beginning. My friend had a nanny and her neighbour called her to say that she hears the child crying all day at home, so for me, a big issue was, what they actually do with your child when you are not there? On the plus side, chances are they will get sick less, and if they are sick they can stay home with nanny. They get individual attention.
From a daycare, you need to be very careful about the teacher-student ratio, again go with your gut. It is not always the fanciest schools that are the best. For me, the biggest drawing card was the teacher, we just got along. Her views and the way she spoke and approached my son made me comfortable. On the downside, they may get sick more often. A child may not enjoy the environment.
With the daycare I use, they have a general timeline but you aren't forced to adhere to it. They will normally tell me e.g. he didnt want to sleep/play/run today etc so he sat with teacher etc etc
Good luck!