OK, I have the older Video Mic Pro which is closer to the shotgun style you mentioned. I would say that it does an "allright" job of capturing audio but 90% of the time I am only using it plugged directly in to the DSLR so that I can improve on the camera's built-in mic...and even then the camera audio is only being used to sync with the audio coming in wirelessly from the lavalier into the H4N....so I'm not really depending on it all that much. What I have works for me but your situation sounds more challenging.
In your situation, I think you may want to actually use some of that camera audio at least for environmental sound, B-roll stuff so I think my best advice is to rent either one and see how you like it before you purchase. Put it this way, if it were me I'd be looking at all the audio reviews to make sure there wasn't something better out there, for instance Senheisser just announced a new small shotgun specifically for DSLRs. Now if you are filming within 5 feet of your subject either of the two mics you mentioned would probably be fine but in a wedding situation I don't think you can count on being so close to your subject all the time.
Steve Crow
Crow Digital Media
http://www.CrowDigitalMedia.com
