The removable face has been a god send on some of my older cars where I could park it anywhere and take the face off and not worry. I had a nice Alpine one IDA-X001 I think, where a little pannel with the buttons came off - nice and neat, but obvious. Fitted in your jacket pocket.
Now... a double DIN with a face off. Thats a pretty new concept for most manufacturers. I know JVC did it a couple of years ago, but it must be new for Kenwood. Unless you have a pretty big handbag - where are you going to put the face?!
Yes, you can remove the face and stick it under your seat or in the glove box... but I bet the tea leafing ba$tards are aware of these tricks and know that you're unlikely to be carrying a 7" widescreen panel around in your pocket!
The Kenwood system looks good on paper. It has better features than the RNS510 - but then you lose out on the OEM look. I guess the MDI in the armrest will become redundant too?
I remember Hurdy changed his standard stereo for a Kenwood one, and then found he had to update all his speakers as the sound wasn't great. Might be worth asking him about it.