A must for smaller cameras
Another great gem from RODE.
If you're shooting with any smaller camera that lacks XLR inputs, but has 1/8" mic in, this is the mic for you. Purchased for use with a Canon T2i, I have found the VideoMic to be invaluable. The camera's pinhole mic is all but useless, and this gives me camera reference audio I can trust.
HOWEVER, there are several things to know when purchasing a mic like this:
1) A mic located on the camera is not going to give you quality dialog recording. Period. This is an improvement for scratch/reference audio, but for usable dialog the mic must be removed from the camera and mounted to a pole. The on-camera mic can, however, capture some ambient sounds that are useful in the post mix when placed subtly underneath music/VO.
2) Cameras with non-defeatable AGC (like the T2i) can't record decent audio. These require a separate audio recording setup (double-system).
3) There is no substitute for a dedicated, skilled sound engineer on set who has a separate and dedicated sound recording system.
Keeping those in mind, the VideoMic is still a worthy investment. The sound is clean and clear, and the built-in pads and bass roll-off are very handy. Suspended in a built-in shockmount helps reduce handling noise.
On the down side, the bands that hold the shock suspension can break fairly easily. The mic comes with a pack of replacement bands, but depending on how rough you are on the mic they may not last long. Also, the mic requires a 9v battery. These are not the cheapest batteries per-unit, though the mic will run for a long time on one battery.
In all, it's a great mic. Don't expect it to be your one and only audio solution, but as long as you know it's purpose and limitations, it will be a stellar performer.