Just after some advice really, never used a snowsuit last year as milder and due to his arrival etc, but now looking at getting one for the colder climes we are having, what is the difference in terms of style, seen some with 2 zips down the front, a zip down the front and inside leg and also ones that zip down the front and thru the legs and up the bum area slightly, which do you find best and what are the positives in each different design please