I had a hotlap. Didn't particularly like the size, or the '60's era technology. Bought an Ultralap from Chad Plavan (
http://www.plavanracing.com/ultralapindex.htm ) and couldn't be happier with it. Well, I could be just slightly happier if it had a little longer cord, but the unit works just great and I love being able to download a session or a day and compare/manipulate/graph the laptimes within Excel.
It is a rugged, modern and functional system which I highly recommend over the Hotlap stuff. And I have been seeing more and more of the Ultralap transmitters already set up at the tracks where I go.
P.S.: With the Ultralap use the motorcycle battery (or other small 12 V gel cell) for the transmitter. This provides the most power and will last all weekend easily.
Tom