G36 superior. It's low weight when compared with INSAS and adjustable butt. There are other things where the G36 might be little better (atleast as per wikipedia), mainly the rate of fire and effective range.
@Mustang,
I use Insas, 4kg is ok, but what i feel, if possible the length needs to be reduce, Their are Insas folded ones which are in use by Mech Inf, And its range is good till 400m with Iron sights, with scopes you can shoot 500m..
G-36 do have all this quality but it is longer than Insas which is not good, Barrel length is slightly longer, And reflex on G-36 is really bad in mud, sand, water where Insas Iron sights just do the job, Overall it gives no big advantage over Insas..
In IA no one likes full auto except LMG, you cannot take good shot with full-auto, Three-round burst is more than enough also it saves ammo..