I haven't played ASB yet, but I have played High Heat. It's a pretty solid game, but I'm not sure I'm blown away like I expected. I kept reading reviews on HH and it was to be the godsend. However, the ultimate stat tracking everyone talks about either must not have made it to this version or it is not very intuitive when it comes to using it.
I liked the game and all, but it seemed a bit too simple. I played on the middle level, and was consistantly winning by 5 or 6 runs.
Your best bet would be to find a rent 1-get 1 free coupon and rent the two games. ASB is supposedly better graphics, but the stats aren't as good.