Asteroid Smart or Pioneer app radio

I had been looking at the the Pioneer App radio SPH-DA110. It appears to offer pretty much everything I need. Nav, Bluetooth and decent radio with room for upgrade. Installer had me convinced that this was the way to go and I am booked in for an install on Monday..

However I got speaking to someoene today who told me that the unit requires my phone to be connected for nav to work and as the decent maps need a data connection it will eat data allowance or worse if I loose my data connection I loose Nav..

Earlier I had been looking at the Parrot Asteroid Smart. Nice unit, again offers pretty much everything I want with the benefit of being able to pair two phones at the same time (work and personal).

Has anyone got any personal experience of either ??

I will be using it for FM radio, music (MP3's mainly) hands free and Nav...

I need decent navigation and I need a decent hands free solution, I mainly listen to newstalk and today FM, the odd cd or MP3.. I wont be using the carious music apps and am not really bothered about any of the other apps (nice if they have some useful ones but not important)..