I've flown several aircraft with the G1000 and I am absolutely convinced that it's the nicest thing out there today.
I was interested to read about the recent G1000 retrofit in a King Air - because having flown a nearly new King Air with the factory fit ProLine 21, I much prefer the way the G1000 works. Although it probably does a little less than the ProLine 21, it is far more intuitive to use.
You can't really knock the G1000 until you've tried it - and once you've tried it, unless you could afford something with the top end Honeywell stuff in it (the Epic is mind blowing), you probably wouldn't want anything else