I did some research on this before having my table built.
I LOVE the look of a racetrack, and it provides a definetive benefit: You can always tell what chips are being bet, and which are just infront of the player.
However as was mentioned it is DANG HARD to pick up cards off of a hard surface.
I did this:
I had a racetrack "line" printed on a full felt table by http://www.lonestarpokercloths.com
Our rule is that once your chips pass the line, (and leave your hand) they are in-play.
Here is a pic:
we could not be happier with the result.
Something to think about for you.