Anyone know much about these App radios?

[Steviesam]

Looking to upgrade car stereo.

Seen these things http://www.pioneer.eu/eur/products/25/299/35829/SP...

Are they any good? I THINK I understand how to get music etc on, but had a question about the sat nav.

If I use the maps, it will use data. SO if I am in France, its going to cost me a fortune! Or am I being even more thick than usual and am wrong?

[Steviesam]

Thnaks. Think I will not bother, a trip through France on Sat Nav will cost too much.