Q: iPad Wi-Fi or Wi-Fi+Cell

I have a brand new Phone 5s, and I am gonna buy also the new iPad Air. I want to have the possibility to be connected to Internet with the iPad, even when there is not a WiFi network available around. For this reason I was thinking to buy the WiFi+Cell type iPad. But my doubt now is the following:

- If I have the iPhone with me permanently available and connected to Internet, I could use this device to create a local WiFi network where I could connect the IPad and therefore I would not need to have the Cell feature in the iPad (saving thus a good money).

-Is there too much difference in using the local WiFi network created by the iPhone, in comparison with the direct connection through the NanoSim card in the iPad?

- Would be worth to pay more for having WiFi+Cell iPad, if I can have the same connectivity through the WiFi net from the iPhone?

Thanks for your comments. I'm just about to buy the iPad (taking advantage of the Black Friday discount) and I have to decide which iPad to buy.

Alejandro Santamaría