You would need to look at the nutrient breakdown of the different types of milk (Tescos website offers this for every food they sell).
I would give more consideration to whether you are going for full fat, semi or skimmed, because that affects the carb content a bit.
Also, lactofree, or not. Again, there are minor differences.
I have found that milk (containing whey proteins) affects my blood glucose to a surprisingly degree, so have eliminated it. I use cream, butter and cheese, which have had the whey removed, and have no problems.
Also, I think that if you check the carb content of bananas, you will find that they have a much higher carb content than the milk.
I find green smoothies, made with the appropriate balance of fruit and veg have a wonderful 'fibre presence'
, no dairy, and minimal blood glucose impact.