I agree, the MFD is the bit of Nav I use the most.
The Kenwood one was worse than MIB1 and by the time you get to MIB2 or 3 its positively retro.
You'd be better off really spending a lot less than 600 quid on a decent non-integrated TomTom really.
I guess the only advantage is being able to hear the sound over any music you have playing.
The real crying shame is that VW refuse to let you retro fit OEM Nav units to their cars
