Originally Posted by Rufus2000

Yes, I-lap is as good as it gets for an infrared system. We're on our first year with the system and I do not regret the purchase decision for our club. It's usb based so it gets all the power it needs from the usb port of your computer, no need for additional power bricks. It's easy to setup and compatible with alot of software since it acts like an AMBrc system.
The free software that it comes with is pretty basic, but we found this one and are extremely happy with it, its free too:

http://www.zround.com/

to be totally honest if you're not a big on-road track and are not doing IFMAR/ROAR events, you don't "need" an AMB.
We race RCGT here and that system is all we'll ever need. The transponders do need a line of sight between them and the sensor bridge as they are infrared, so you just mount them inside the body just below a clear windshield. If you can't or won't do that then yes you need to spend 5 times as much and get the AMB.