Same here with my iPad-- very smooth and responsive.
In the past, I've found that if it does lag at all, it's mostly due to how I touch the screen. I find that, with my iPad, it responds best if I use the tip of my finger and make sure that it doesn't slide across the screen as well.
I will say, however, that I never had any luck with Nike Level 61 balls that you're playing. Those did always seem to lag for me, especially on pitches. The Nike Level 71 and 81 balls work much better for me.