Hard to define "better".
Yes, there are cameras that are technically better. And there
are cameras that are designed for shooting video (the DSLR's
are designed for shooting stills) that many DP's prefer. When
adding all the necessary accessories the cost of a good HD
"video" camera is about the same as using a DSLR.
But "better" is actually a preference in most cases. I know you
are in the process of hiring a DP. My advice is to use the camera
your DP is comfortable using. The 5D and 7D are fine cameras
for shooting a movie, but not the "best" choice.