Like Pegsy posted, the IR types of systems are a little unreliable in true outdoor conditions.It all depends on your needs I guess.We just put in a Robitrinics scoring system on my oval.Seems to work just fine for that, but it would probally give us some problems if we were trying to run off-road with it.The robitronics set-up is nice.For under $500.00 you can set one up and get enough spare transponders to run 7 cars at once.Not too bad if your just starting out.For another 120.00 you can end up with 10 transponders and could just use them like house transponders.