My favorite apply is a Red Delicious for taste, which makes sense because they tend to have more sugar and less fiber than other types. Darn sweet tooth! But the nutritional value is not much different than other types.Try to eat organic apples and avoid any that are bigger than your fist- these are stretched with fertilizers to make them bigger, which is all water and no nutrition.
There is no significant, objective nutritional difference. Some green apples may have more sugar/gram than red, and some red may have more sugar/gram than green. Other factors' contributions' are much more significant (age, ripeness, etc.).