Believe me, you can without a question tell a difference between the $600 high end decks and those in the $1k+ range. To all those saying 880, while it is a nice unit it really doesn't hold a candle to the higher end stuff. I picked up a P9 combo myself recently and the difference between it and the 860/880/9855/9835 I've used in the past is UNBELIEVEABLE. Everything has more detail.
About the Kenwood X991- No 3-way crossover. This is unfortunate for a lot of people, hopefully you aren't one of them if you're considering it.