Babysitter Or Day Care?

What do you think is better? Have a babysitter or your child go to a day care? I have a babysitter but I start to worry about the education that my children receive. Older child, about 7 years, already goes to school starting this month, but the smaller, 3 years and a half, sitting all day with the babysitter. I think that I take my child to day care even if it will be very hard for him. However, I do not know what to choose: babysitter or day care? Please help me!