i just bought one recently and i must say it's a great thing to know what your performance is on the track. out of about 30 packs that i've run, i think it's only missed 1 lap, but it could've been when i was side by side with another car beside the LCS unit, and the IR signal was blocked.
It also shows every lap, and I read it out to see if certain setup makes me consistent and if certain setup gives quicker laps at the expense of consistency.
You get the point.
The only bad thing i could think of is power consumption. Does anyone knows how much power it takes?