When comparing kilo and tundra(arguably the best sniper)with builds that i regularly use, we can see that kilo has-
-faster fire rate
-faster movement speed
-faster reload times
-same ads time
-faster sprint speed
-faster sprint to fire time
-less flinch
-higher steady aim count down
-same hitboxes(one tap above legs)
The tundra only has more bullet impact so more penetration but that's about it.
The kilo is by far the better option stats wise but I barely see it in ranked. Even the spr with the correct build is good but rarely used.