My best friend Joe has a video camera and says he'll film the day!
By all means, you should consider that option. The problems can be many though. A lot of people like to 'zoom' the camera in and out producing bad focus and a lot of 'shake' which as you know can be very hard to watch after a few minutes.
The sound recording facilities on budget video cameras leave a LOT to be desired. We use professional shotgun and radio lapel microphones, NOT the inbuilt camera mics and there is a very good reason for this. We use these pro mics because they can hear every word you say at a distance so when you're taking those vows, a pro mic will hear and record those words and nothing else. A budget video mic will pick up every sound, to the side, behind and in front....each and every cough, children chatting, it doesn't bear thinking about.
After all, Joe is one of your guests and a friend and he's doing you a favour. But what if you don't like the results?
Being a pro cameraman, I'm not at your wedding to enjoy myself, I'm there to do the best job I can without distracting you or your guests.
I use High Definition video cameras that cost a lot of money. You can buy a high def video camera nowadays for £300 but don't be fooled by that word.
All HD means is that the signal has so many lines of resolution but unless you have three chips inside that camera and a GOOD lens on the front, it isn't going to look anything like a pro cam video. That's why I and other pro video camera operators pay £5000 or more for each of my cameras.