It's easy to focus entirely on whether the camera will connect to the iPad. For a useful professional workflow, however, I think the more important question is what happens to the photographs after they arrive.
Capture One Mobile can form part of a larger Capture One workflow rather than existing as an isolated mobile application. That makes it possible to begin the job on location and continue it later when you're back at your main editing system.
Sessions can make sense for tethered work
For jobs built around a specific shoot, a Session-style workflow is particularly logical. It keeps that piece of work self-contained and makes the transition between capture, selection and later desktop editing easier to understand.
External storage changes the equation
Current versions of Capture One Mobile can work with compatible external storage, including working with Sessions or Catalogs stored externally and shooting tethered into external storage. For larger jobs, this can make an iPad workflow considerably more practical than treating the tablet's internal storage as the only destination.
Before an important shoot
Test the complete chain: camera, cable or wireless network, iPad, Capture One, power and storage. A tethering workflow is only useful professionally if the entire system is predictable before the client arrives.