*** V7 ***
My HK Keyring Cam (Version 7). Needed to get a class 6 Micro SD card to get smooth jitter free video, even with cam set to 7 FPS, picture still jittery on a standard speed memory card. I had issues with battery life (only get 7 mins video), not charging to 4.2V. The V7 has a firmware upgrade (flip, FPS, remove date stamp).

The spy cam camera's big downer for RC use, is your never sure if it is recording or off, as this is the LED indication for both states. So it flashes when you start recording then LED goes off "REC mode", however if battery runs down LED goes off. So is it in "REC" or "OFF" at any given time, you can't be sure??? Spy cam indication design sucks for this application.

*** V3 ***
I now also have a version 3 from ebay for $9 delivered. Battery life is better, but still inconsistent, single record time when fully charged is anywhere from 10-35mins so far. V3 pros/cons over V7:
Cons:
* No firmware upgrade yet "Sep2010" (can't remove date stamp, invert, FPS).
* Auto contrast is a bit hyper sensitive and picture can go to dark at times.
* Stretches horizontal from 640 to 720 (just re-size it with free "avidemux").

Pros:
* Smooth 30FPS on a standard class2 memory card, V7 needs class6.
* Way better sound, no chop/buzz/loss like V7.

Conclusion: Definitely go the V3, be aware that finding a GENUINE V3 is now more difficult.


Keyring camera info: http://chucklohr.com/808/#webcamdriver
http://www.rcgroups.com/forums/showthread.php?t=1203292