I bought this for the advertised HD capabilities, only to find that the 1280x1024 pixel frame size video is software interpolated and therefore, not only you do not get extra HD detail you get larger files which subsequently reduce recording time (approx 1 MB/sec, so you will get just over one hour of video on a 4Gig card as opposed to 2 hours).
In addition, although this records higher frequency sound (apparenly 24KHz), the compression employed is very high (low bit rate) which results in artefacts - sounding like hiss and inteference (not usable for any concert recordings).
The pen looks nice, works, it arrived fast (included a 4 MB microSD card!) but the quality is NO better than those pens recording in standard definition video of VGA resolution (640x480 pixels).
Finally, in my experience, cameras like this one that use microSD cards are more reliable and last longer that those that work like a USB stick.