There was an earlier comment about the Kenwood system not being fully compatible and I'm still trying to find out what that means as I'm seriously thinking about getting one for my soon to be GTD.
I had a look at one on display at Alan Day London City today and think that it looks pretty good. The only thing I didn't like was the choice of the 3 skins, but understand that you can replace with your own background through use of external media.
I was also told that fully compatible with MFSW on a 2009 + Golf VI, so at moment can't see what the RNS510 + Fiscon would give me in addition other than that OEM feel (but at higher price).