I never used it for looking up contacts but I had problems when I would use it with media player. It would repeat back to me what I said but never do what I said (next track... next track.... I SAID Next track!!!)
Actually that is the best use I have found for it so far. Driving down the road with the Axim hooked up to an FM transmitter I can listen to MP3's and tell it what to play without having to take it out of its case. Very nice on long trips.
Too bad it doesn't work well in WM 5