Confused: 5D MARK II - H4N or Rode?

If your firmware is updated, you won't have any problems with drifting.

Canon fixed the 30fps / 29.97fps issue, so they synch up perfectly. Even before the firmware update though, all you had to do was set the audio speed to 99.9%, and it matched up. Now, though, there's no issue at all.

The zoom is awesome.

thnaks. i'm buying it

H4n for audio because it provides you with a remarkably high quality recording for 300 bucks US.
It is vastly better than the camera's track especially in low end (read "warmth" in spoken word, or "fullness" in environment or music recordings). The 5d has a cheap preamp and A/D converter that is hard to overcome. Use the H4n and get PluralEyes software for easy sync.
There is no drift in sync worth mentioning within the 12:50 clip length you can record.
The other great thing about the H4n is that you can place it physically close to your source, and lower any annoying background sound...ex: shoot a babbling brook from a roadside pulloff with the H4n placed far from the road and near the stream, pointed away from any road noise willbe better than any on camera sound.
Have fun!

great Thanks for the advise!