Sniper of course due to its bigger and better engine, its a newer model and its of course an improved version of its older brother, the X1.
It's actually not fair to compare the two cuz they don't belong on the same engine class. Better yet, the X1-R vs the Sniper. I've heard the X1-R performs better on circuits than the Sniper. I've tried using both and found out that X1-R has better maneuverability over the Sniper. It actually looks better too! Too bad they discontinued X1-R a few years ago.