I had few flights with the micro and noticed that while it works as
advertised, the fact that it has no audio alert makes it useless IMHO.
Although it was velcrod on top of the glare shield in front of my eyes,
the only time I noticed the leds is when I remembered to look directly
at it, otherwise it is not noticable when our eyes are focused on
infinity.
I replaced the unit with a Monroy which has audio alert as well as
visual alert, and indeed most of the times I hear the alert before I
notice the leds. The Monroy ATD-200 doesn't take altitude into account,
so I do get alerts from airliners flying above, but the false alarm
rate is low, and it doesn't hurt to look around anyway. At the minimum,
it reminds you to look around when there is a higher probability of
conflict. This fact by itself worth the investment IMHO. Unfortunately
it is not very effective in detecting gliders, since most gliders
either don't fly with transponders or turn them off to conserve
batteries when away from TCA. I was suprised as for how few alerts I
received from gliders when flying over the White Mountains.

Ramy