I truly think they both hav their positive aspects. I feel that I am a bit "well equipped" to answer this, as I have lived in both areas growing up.
I have gone from a city with lights and action allll the time to living on a dairy farm.
We (my hub and I), after living in a small city for 5 years have just recently made the big move back to the country. I am so happy we did. FOR US it makes sense. We are used to country life (my hub was born in the country) - we always talked about bonfires with friends and family, playing with our kids in our big fenced in yard and waking up to quiet. We are so blessed that that is now a reality.
But that is just what works for us. A large reason why it works is because, that is what we are used to.
saying all this, we were quite happy in the city too, but something was missing. But if, for some reason, we were unable to move back to the country, we would have been ok. Because we have each other.
So after this long winded answer I would have to say that BOTH have their advantages. Both offer amazing learning opportunities for little ones. At the end of the day, being with those you love and being truly present, is what matters :)