Hey Sean,
I bought the 5D as a casting/location camera, and was shocked at how good it was. It's a great camera for the money, but the more I use it, the more I see little things that bug me about it, over the 1ds2. The ASA is hard to change, the meter is harder to read than the 1ds2, and for some reason, the meter seems to get fooled easier. I think the 5D is great "walk around camera", but when there's money on the table, which there is in your case, you can't cut corners. The 1ds2 is the only one. I have also fought the color palette with the 5D; a bit too saturated for me, but I'm sure that amateurs love the pop, right out of the box. I rarely fight the colors with the 1ds2; actually, always love them. The 5D has a role; just keep it as a "fun" camera, but never put that grip on it; keep it simple. Adding that grip is like when Hollywood costume people add those fake muscles underneath the clothing of actors; just does not feel right. Let it be what it is. Don't try to make an EddieHaskell camera into a JackieChan camera.
Hope you're well. Take care,
Mark