Animation speed can be altered. Add "delay(x)" to your animation set name, "x" being your choice of speed. Values are from 1-10, 1 being the fastest. The default speed isn't very smooth so that's why you're seeing jerky and slow animation. A speed of 1 is pretty much no delay at all and is certainly the smoothest, but it means creating a lot of frames so I usually stick to a speed of 2 in most cases.
There is more help on this page too, tells you everything, including this. Scroll to the very bottom and it's the 4th from the last. Hope that helps
http://xion.r2.com.au/index.php?page=layerref
Peace, Lance