One thing to try is to get your hands on a couple of different models and see how the look and operate. Perhaps at the rally there will be a few there. Otherwise swing by any track event and look around. Most guys there are pretty cool and wouldn't mind showing you how their "boxes" work. The neatest, I think are the ones with integrated video.
NASA in our area uses -- a hot lap timer which is a breeze. Basically just times/stores the laps. I think AMB also which has more features too.