which is the better for video+photos for weddings and why?

I would say the 6D. It's newer, dramatically better in low light, adds 720/60p, and doesn't over heat (not sure if the 5D2 had an overheating problem like the 7D and T2i did).

I may be late, but I have to add the price of SD flash storage compared to Compact Flash into the equation as well.
The dSLRs being sold in EU have a limit of 30 minutes for continuous video operation, though, so this may be a negative matter. I bought a new 6D via Ebay in August 2014, and I am pretty satisfied at the moment.

N.F.

The 6D has horrible Moire problems and is not a good choice for video. It will take stunning photos and most of your video will be o.k., until someone shows up with a plaid shirt, or your back lighting poses problems.

Your better bet is the 5D Mark III unless you primarily shoot only photos, in which case the 6D is a better choice.

Your better bet is the 5D Mark III

Serggio was refering to the 5dII compared to the 6D, I don't think the 6D is that much worse then the mark II when it comes to moire. The 6D however outperforms the 5D mark II in low light so that might be a better choice.

Take a look at Mosaic Engineering anti aliasing filters for non-5D3 DSLRs.

Dont need to the 6d is fine only the odd moire not that bad in regard to everything else.