We race every week and use the i-lap counting system with alycat software. Because of the huge range of personal transponder numbers almost everyone has at least one transponder.
I did a very extensive amount of research on this subject and hands down the I-lap system was the best.
Robitonic system is limited by the software it can use and the transponder size his larger. Some of the bodies don't have much clearance.
Giro-z system is also limited by the software and the small range of transponder numbers. 24 total i think.
core system is very limited by the software. Transponders go bad very easily and the hardware is flaky.
I-lap system can use almost every software program on the market. The size of the transponder is good for mini-zs. Gyro z is a tic smaller. Customer support is awesome. When i was setting up the system Craig worked directly with me when i had questions. The system works great on 10th scale cars as well. Inside and outside. The bridge size is expandable to 24 feet. The computer system can be 150+ feet away from the bridge. Theoretically it should be capable of 2000+ feet.
There is a group of guys that live near me that also bought the system and use it in the summer for their gas trucks. Then in the winter they use it for mini-zs.
I wrote up a detailed review on mini-zracer
http://www.mini-zracer.com/forums/sh...ad.php?t=26194
hope this helps.