Get the cellular version. If you don't, you'll regret it.
Why waste extra cash on a cellular version, when you can as well connect your IPad via Bluetooth to a phone device and use the cellular connection there.
You actually don't need cellular connection on the IPad if you simply follow these recommendations:
1- Preflight your IPad at home using Internet connection before going to fly, e.g, full charge the device.
2- Download all current charts and flight information (NOTAMs, etc)
3- Connect your IPad to your external GPS device and complete all the flight planning required.
4- If in-flight charging is possible in your plane, take the necessary cables and adapter with you.
WP