A.J.
Hi Dawn,
Best wishes to you with your decision that lies ahead. It is never easy making decisions for our kids, and you definitely know your son best. I have to tell you this may not be what you want to hear, but the right choice isn't always the easiest. Sorry I am curious how often he has melt downs with you at home or in the store? Are their times when he is tested and does not get what he wants? How does he handle that with you and your husband? Do you ever give in to his wants? As a teacher, it is my experience that a child who is doing this with another adult may be ruling the roost at home.
If this is the case or not, he needs to learn now to respect authority before he starts school. This means very strong consequences and no going back on your word. I agree with the others here, he definitely needs structure and consistency. Perhaps more than he is getting at his current daycare. I suggest you continue to work with the daycare lady on some serious plans of action. I have used several positive behavior plans with children that work. That way you can start any day fresh and focused on his good behavior giving him rewards for that... but still when a negative behavior occurs, the care taker must be ready with the consequences. It is crucial that a plan is in place that he understands before the behavior occurs that way everyone is ready and prepared to help him through this tough time.
My sincere best of luck to your family and the success in your son,
AJ